And that is even a better advice than mine.

If I get it right sites are based on the same topic, so interlinking them carries both user and search engine value (maybe a little bit less for engines than for users as google maybe knows that you own both sites so it gives less value to the links). When you do your linking just keep in mind what pages would you like to rank with and hw pagerank flows so do your job based on that http://perthseocompany.com.au/seo/tutorials/a-simple-explanation-of-pagerank (thanks ALan). Good luck!

Repeating just a snippet of infromation is not considered to be duplicate content. So if you have a few lines of text appearing repeteadly somewhere on your site, or multiple occurances of a video taht is not a duplicate content as long as the page contains enough individual information.

The other thing is that engines can't really find out video content they just make conclusions based on the descriptions you give them. Vary descriptions and titles.

It has some impact bust not very serious, I would say converging to zero. I think writing a good description that answers the serchers's querry and generates clickthroughs is more important than stuffing your kw in the first few words.

in analytics you can actually see the links that send you visitors. You can have a look at them under traffic sources and linking sites. However this is not a complete set of sites linking to you.

Open site expolorer here by seomoz, or you can try open site explorer by yahoo. Here you can find a list of some more if you would like to try multiple ones: http://www.toprankblog.com/2009/11/1-seo-tools-for-tracking-inbound-links/

Hello,

This is seriously hurting your seo. The best way to get it over to implement canonical links in the head section of each page, so that it will tell google which page to display in the serps. You should choose the all lovercase letter one with no .aspx ending.

You can use 2 h1 tags but if the first one is empty than you surely don't need that