thanks for the reply dan-572483, that's my concern too.
I think I will try with 70-450 and then 70-448.
I heard that 70-450 it's a very hard exam and there is not much material of it ( I found only one book that I have now: SQL Server 2008 Admin from Sybex ) and a Trainsignal Training also ( advanced SQL 2008 admin ). That is the material that I have right now.
The CBT Nuggets videos are pretty good, you should check them out also. You're in a more comfortable position than me though. All the way until July to study :o I'm hoping I'm in a position to take it by the end of next month (so I get 2 tries for the price of one, worst case scenario
)) since I still have to take the 70-432 exam before July too (less of an issue).