Well you probably formatted those in drives in XP previously as 'dynamic volumes' instead of 'basic' types. http://support.microsoft.com/kb/308424
Dynamic volumes offer some more flexibility in management but run into this very kind of problem.
If you don't want the data on that disk just go back into XP and delete the volume in 'computer management' and then leave it unpartitioned or formatted for the Vista install to chew on.
Control panel>administrative tools> computer management> storage>disk management click on the drive and then 'delete partition' - this may not be the only way but it should get you there.
If you are trying to preserve any data on that drive then you may be able to 'convert from dynamic to basic' in that same computer management section - I have not tried that in a long time so it's a little foggy..
edit: while in XP you might also need to convert the disk back to basic - it can't hurt to go ahead and partition and format it there as a 'basic disk'
Hmmm, I did try that earlier. Went to Control panel>administrative tools>computer management>storage>disk management and delete the partion and left it like that. when I went to install Vista, under Type it didn't say Dynamic anymore but it still says the same thing at the bottom of the screen
"Windows cannot be installed to this hard disk space. The partition contains one or more dynamic volumes that are not supported for installation."