Off the top of my head I believe there are 28 Democratic Governors and 22 Republicans.
MyGOP is correct, it is 28D-22R
As of January 2007, here are the states with Dem Governors:
AZ-Napolitano
AR-Beebe
CO-Ritter
DE-Minner
IL-Blagojevich
IA-Culver
KS-Sebelius
LA-Blanco
ME-Baldacci
MD-O'Malley
MA-Patrick
MI-Granholm
MT-Schweitzer
NH-Lynch
NJ-Corzine
NM-Richardson
NY-Spitzer
NC-Easley
OH-Strickland
OK-Henry
OR-Kulongoski
PA-Rendell
TN-Bredesen
VA-Kaine
WA-Gregoire
WV-Manchin
WI-Doyle
WY-Freudenthal
And with Republican Governors:
AL-Riley
AK-Palin
CA-Ah-nold
CT-Rell
FL-Crist
GA-Perdue
HI-Lingle
ID-Otter
IN-Daniels
KY-Fletcher
MN-Pawlenty
MS-Barbour
MO-Blunt
NE-Heineman
NV-Gibbons
ND-Hoeven
RI-Carcieri
SC-Sanford
SD-Rounds
TX-Perry
UT-Huntsman
VT-Douglas