WordPress MU

are any SEO mods you recommend for wpmu?

thanks

If you properly check all your themes and your code it should validate xhtml compliant which is a major plus for google pageranking. Beyond that using accurate meta keywords and descriptions helps with other search engines a bit.
Finally (and this is the biggest one after xhtml compliance):

Make sure you have a lot of textual content that is easily read by regular viewers (hiding text in background wil screw you with google). google checks pages for content in place of keywords.

Being honest with your users and search engines will earn you hire pageranks naturally rather than through plugins

Good question though :D

I have the opposite problem - getting Google to stop crawling my site so much.

andrea, we can swap domains if u like :o)

thanks corourke, it sounds like wpmu is ready out if the box (no specific seo mods recommended)

Two plugins that I would recommend are:

Airabove WordSpread http://www.airabove.com/wordspread
By Robert Arnesson

and;

inlineRSS http://www.iconophobia.com/wordpress/?page_id=5
from iconophobia.com

Others may swear by the Google Sitemap Generator for WordPress ( http://www.arnebrachhold.de/2005/06/05/google-sitemaps-generator-v2-final ) but I have found a simple robots.txt file, properly formatted, and using the built in date and name based permalink structure (Admin -> Options -> Permalinks) to be more than adiquate for most search spider bots.

Tying in with corourke's sugestions and also revealing why Google likes my site(s) so much: write plenty of relevant content on a frequent basis. Luckily, on an MU site, this should be happening multiple times per day. Post titles that are relevant and include search terms that you want people to find you with go a long way, as does having a large body of work for Google to crawl.