There are various emulators, validators, mobile analytics packages and one mobile-specific keyword research tool available to help optimize a site for mobile devices. I won't list them all here, but I keep a running list in my bookmarks:
http://del.icio.us/brysonmeunier/mobile_seo_toolsIf you're interested in the subject beyond tools, I blog about it regularly at my Natural Search and Mobile SEO Blog:
http://www.brysonmeunier.com.
Best,
Bryson