Hi Dana & Marshall,
I think you're making the right choice moving from Joomla to WordPress. I also think Dana is completely correct about speaking to an expert about managing your migration. I also believe that you would be best off to add a link saying read more and either allow it to expand the page or bring the customer to a new Page That Way, Google gets the content as well as the customers who choose to read it. I would not destroy the content.
Your links are something you want as few parameters as possible in so to not keep adding / to your links. Use SEOmoz's get local tool to help you optimize your website for whatever city you are interested in optimizing it for.
However and I would like Dana's opinion on this. I have seen fantastic results using CMS to CMS the links are right here.
http://www.cms2cms.com/
http://app.cms2cms.com/wizard/
This is an extremely inexpensive way to move everything over including all the 301 redirects.
Google suggests you check for broken links prior to moving your website.
I suggest if you're running Windows use
http://home.snafu.de/tilman/xenulink.html
Xmenu as they suggest however if you're running a Mac or something else and you wish to use a different tool or a web interface here are some suggestions.
Using one of the free tools below if your site is over 500 pages Internet marketing ninjas tool can go up to 1000
if it's less than 500 use screaming frog spider SEO
http://www.screamingfrog.co.uk/seo-spider/
Also if you want a web interface as opposed to a download Internet marketing ninjas this web-based where screaming frog downloads for free to Windows, Mac and Linux they do charge if you want to go over 500 URLs.
Internet marketing ninjasIs it
http://www.internetmarketingninjas.com/seo-tools/google-sitemap-generator/
When you make the move you're going to want to let Google know this ahead of time. Using Google Webmaster tools
http://support.google.com/webmasters/bin/answer.py?hl=en&answer=83106
Important: In order to use the change of address tool, make sure that you've added and verified both your old and new sites, and read the guidelines on moving your site to a new domain. You should be especially carefully to use 301 redirects to tell search engines about the new location of your pages. In addition, make sure your original site is not a subdomain (for example,http://newsite.example.com).
http://support.google.com/webmasters/bin/answer.py?hl=en&answer=83105
You had mentioned you are changing IP addresses but staying with the same host. Here's Google's information on this.
http://support.google.com/webmasters/bin/answer.py?hl=en&answer=83106
I would strongly suggest using the managed WordPress host unlike Joomla WordPress is a much more popular content management software that's a good thing and a bad thing considering the increasing frequency of forced entry attacks on WordPress and the fact that your website is a business I would strongly suggest a managed WordPress host.
By using a managed WordPress host you will have a site that is protected using extremely powerful combinations of firewalls and other methods specifically to protect WordPress. If your site is ever hacked and this is universal for all of the web hosts I'm mentioning you will get your site fixed for free and if it is ever blacklisted it will be room moved for free almost instantly as they all use http://sucuri.net/
Your site backed up least once a day, have access to download the backup in addition you can have it sent to you as well. Have the increased speed Google and more your customers over will care a lot about. And increased security the hosting companies I'm about to suggest all only host WordPress sites this is a big plus as anything that happens with your site they are going to be able to most likely fix for you this is not the case at other hosts where they just have to keep the server up and running. Managed WordPress hosting is in my opinion the only way to go if you're running a business.
My suggestions are WP engine, Zippy kid, Web synthesis and Pagely
WP engine a great host that is extremely fast content delivery network is available they spread $29 with CDN $49 25,000 visitors a month 24 7 support along with phone support for 3rd level. Pro perks at
SEOmoz offers you the ability to get 4 months of free hosting.
Zippy kid a great host two extremely fast content delivery networks built in base price $25 100,000 visitors a month with that you get managed anycast DNS (DynECT is normally $200 a month), Akismet is free instead of the $5 a month norm, right now they are offering a site optimization by engineers from Google and Net DNA at no cost to anyone who has a site with them. 24 7 support along with phone support for all levels.
Web synthesis a great host from copy blogger they have a very fast server and will help you integrate a content delivery network they suggest using media Temple's CDN their base price is $27 a month with the CDN it would come up to $47 a month for 2,500 page views a day. While they don't offer phone support they do answer tickets very quickly.
Pagely a very good host backed by one of my personal favorites fire host they have a strong emphasis on security as do the others they charge $24 for their base plan of 25,000 visitors a month however if you want there content delivery network you must choose their business plan at $67 a month plus pay for the CDN in additional $25 a month making the total cost just under $100 a month. You can get 30% off Pagely for life using SEOmoz Pro perks.
If you don't mind paying for the content delivery network my choice would be WP engine however if you want that same level of superb hosting & want everything you need and require phone support Zippy kid makes an excellent choice with 100,000 visitors a month and no need to pay for other things like AnycastDNS for spam plug-ins they also offer full git integration along with the complete site optimization it makes an extremely good deal.
Don't get me wrong you cannot go wrong with any of these choices. However I would take into account that WordPress has a database and that makes it slower than pure HTML so using a web host that specializes in WordPress along with a strong content delivery network will make certain your site is extremely fast I find that it is faster in a regular HTML site when using one of the suggested hosts.
I hope I have been of help to you,
Thomas