Via Nokia Blog Forum. Some services to test if your website is ready to go for mobile or not.
As far as I know there are two service providers:
Bango gives you a score from 0 (not designed for mobile phone) to 5.
Ready.mobi gives a much better analyses of your mobile web site (Readiness, Size, Time & Cost for the visitor and if it is W3C valid).
Check here if want to be sure that your mobile web site is conform to the W3C mobileOK Basic Tests 1.0