hi just share around , 500D has spot metering , digic 4 , better noise reduction , higher mega pix (14 bit),9 af point, bigger and better lcd 920k dot . higher iso peformance .u have to weight what u wan try to get hands on both unit . if u can just go ahead with 500d no regrets .
If u are really going to get into photography, get a 500D. if u r not too serious and have more flexibility than a point & shoot, get a 1000D.
I got a 1000D, my dad got a 500D. For $300, there is a big difference in the picture quality and functions. if I could turn back time, i would have got a 500D. But it all depend on how much u want to take up the hobby.