The motherboard has a X16 pci-e graphics expansion slot, so you are good there.
But, the 8800GTS is an older and more power hungry card that some suggest needs a 500W psu.
Read this chart:http://www.realhardtechx.com/index_archivos/Page362.htm
I would go ahead and try it, particularly if your psu is a decent brand and quality.
If the card does not run or you get artifacts, be prepared to change out the card or the psu.