How important is the 301?

Thought I'd ask this here at WebmasterWorld...

My site is hosted on an IIS server and (naturally) my host provider will not work with me on getting a 301 redirect in place.

I was thinking about switching host providers, to one using apache servers. What do you guys think?

Does anyone know of IIS host providers out there that allow admin access (somehow) or possibly will put 301's in place?

I think my site is being hit with duplicate content penalty. Here's the G results when searching with the "site:" command...

site:www.mydomain.com = 100+ pages
site:mydomain.com -www = 28 pages

These non-www pages include titles and text. Some are supplemental, some are in the main index.

I do not use ASP at this time so the asp redirect solution is not an option. I'm really looking to forward mydomain.com to www.mydomain.com.