Just found this as well:http://raventools.com/blog/ultimate-list-of-relauthor-resources/

Might help..

Hi Jodi,

Keep up the good work. If you are creating useful content in niche related blogs, that is educating or entertaining to the users you are doing exactly what search engines want.  Adding value.

Of course, there are other non-SEO benefits too, because these are reputable sites.  But I'm wondering how this helps my SEO?

If you are creating great articles that people are sharing and interacting with, the article will get linked to naturally and gain credibility. Just make sure your are linking your guest blog posts to your site via anchor text in a natural manner. 50% URL or Brand name, 25% long tail anchor text, 25% the Exact keywords you want to rank for.

Hope this helps.

Having site wide links like that can look like they may have been paid for.

"I know that all other things being equal (1 link from 10 domains > 10 links from 1 domain) but is (1 link from 10 domains > 100 links from 10 domains)?"

1 link that gets relevant traffic to your site is worth more than 100 links that are not relevant to your site. It's not about how many links it's all about what type of content created that link. In other words building a natural linking profile is not link building, it's creating real content and sharing it with the right people who will help that article get real natural links.

WIthin your Google Places account you should be able to place all the zip codes/areas that you provide service in, I should not be limited to one area.

The key to getting a higher placement is NPA (Name Phone-Number Address) citations.

Getting listed in all the major relevant to your niche directorys and making sure that the pages are easily crawlable.

Its also beneficial to have you NPA on the footer of your site.