I currently administer 3 websites, all of which have domains and are hosted in different places. I was wondering how easy it is to roll those sites into DH, and how easy it is to manage multiple domains through DH.

I must say i’m slightly disappointed about the BT policy, as i’m heavily counciling one of my clients to start a podcast and had hoped to distribute it through BT, but since bandwidth probably won’t be an issue at least for a while it’s no big deal.

any insight would be appreciated…

Should be fairly straight foward: take a moment to read the articles in the ‘Transfer hosting’ section of the DreamHost Knowledge Base.
All the best -

Managing 100 domains is as easy as managing 1 at DH, since all you do to switch domains is pick it from a list on the left side of the page.