I've installed
Member Bots 1.0 - Allow bots to act as members,
vBSEO Google/Yahoo Sitemap Generator for vBulletin 3.5.x & vBulletin 3.0.x ,
Google sitemap for the vB Archives. Redirect human and robots, and vBGSitemap - vBulletin Google Site Map Creator.
I'm not even sure if any of them work like they say they're supposed to, and I know some of them don't work fully/correctly because my server doesn't have that rewrite thingie from apache.
I do know that I've read some SEO books and search engine optimization books, and the tips in there helped me out the most. Like with that they suggest for meta usage, selecting the correct keywords and descriptions, etc. (I do have these books hosted online, so feel free to pm me for the link if anyone's interested).
Also, since I use vBadvanced CMPS as my homepage, I think personally, it's probably the worse thing you could use to help with getting SEO'd since bots won't read it correctly. (most books say that the bots take your meta keywords and then look for those keywords again on your homepage, and give them points for if the keywords come up again and if they're underlined, bold, itialic, h3,h2,h1, etc.) So what I did is create a paragraph of text, and have the paragraph hidden underneath my banner by using some css scripting. :devious:
Edit: I think it's called BIR (Bob Image Replacement)