PCI Express are normally black, yes. AGP are brown and PCI are white. And yeah, the x1 sockets are like an inch long or something. They don't compare to standard slots for size.
Before you celebrate finding a PCI-E slot and rush out and buy a 8800GT, you'll want to check your power supply. You'll need a good quality 400 Watt PSU ( or quite a bit higher if it's not a good brand ) to run a 8800GT. Some manufacturers say higher, but I think that's just because they know that some PSU manufacturers bump up their wattage stats.
Before you celebrate finding a PCI-E slot and rush out and buy a 8800GT, you'll want to check your power supply. You'll need a good quality 400 Watt PSU ( or quite a bit higher if it's not a good brand ) to run a 8800GT. Some manufacturers say higher, but I think that's just because they know that some PSU manufacturers bump up their wattage stats.