How is Fallout 3 on the PS3 compared to the 360?

Actually, playing Fallout 3 on PS3, and XBOX 360, there is a huge difference. Especially when playing in HD. The processor in the PS3 handles the games graphics slightly better, in fact playing in HD with Xbox 360 you notice the sky isn't as smooth, and playing in HD is horrific on XBOX 360. Also, having the DLC's for PS3 released at the same time was excellent because all the DLC's ran much more smoothly together. All in all, it depends on what Definition your using. PS3 takes the cake in SD, and HD.

I found the graphics slightly better on the PS3 than the 360. However on the 360 there was a great contrast between daylight and night time making it very hard to see at night and make it seem more realistic/challenging. Both systems will occasionally freeze (make sure you save before going anywhere near mothership zeta on the PS3), but I have seen the PS3 actually unfreeze more often than the 360.

the same, its best on the PC though.

its exactly the same.