No, not directly.
A standard VGA PC monitor will be expecting sync signal with a frequency of 31.5 khz and most PCB's along with most games consoles that can output rgb will put out a sync of approximately 15.7 khz.
You have 2 options if your hell bent on using a monitor tho. Either get one that supports multi sync .. a lot of modern Plasma and LCD screens that have a VGA connector will do this
OR
Get yourself an "upscan" convertor or scandoubler like this:
http://www.play-asia.com/paOS-13-71-86-49-en-70-5w4.html
Thatll do the trick if you REALLY want to use a standard PC VGA Monitor.
MrS
P.S .. and before anyone else points out, yes , there are a few more modern games that DO output a vga compatible signal but nowhere near the number that output regular RGB+SYNC.