Google Cache problem

I am working on one of the site that i see has some problem... site is listed under both version with www and without www...

when i search mydomain.com in google(without www) it comes up with old page old title, desc and cache of site "as retrieved on 29 Jun 2005".

And when i search www.mydomain.com (with www) it comes up with current page title, desc and cache of site "as retrieved on 28 Nov 2005".

Now when i search site:mydomain.com index page comes up with both version (with www & without www)... both with lastest title, desc and cache.

mydomain.com shows PR 0 & www.mydomain.com shows PR 5.

Can anyone tell me what may be the problem? Will 301 redirect solve problem? (I guess it should. More interested in hearing your views & comments.)

Anyone with similar problem?

I hope i was clear... let me know if you need any more detail ...

google cache problem with www & without www