I want to migrate accounts from a hosted service to an Exchange 2010 Server. It is IMAP to MAPI, so I wonder if there is a fast way to do this. I know that exchange 2007 had a special role for this so I hope there is a similar way in exchange 2010. I want to migrate around 50 accounts
I am unclear what you mean by " I know that exchange 2007 had a special role for this". There is no IMAP to Exchange copying functionality in Exchange 2007. There is the Microsoft Transporter Suite (which isn't actually a part of Exchange 2007) and Microsoft confirms that they aren't updating it for Exchange 2010.
If I were in your shoes I'd look at using imapcopy (or your favorite IMAP to IMAP copy utility-- there are a number out there) to copy data from the IMAP accounts into the new Exchange mailboxes.