I was browsing GT and came acrossed some videos, I think some might be a little old but I hadn't seen them and I'm sure many others haven't as well. I promise you if you're interested in this game at all they are worth watching...the first 2 are decent quality but the last 3 are very low quality and unfortunately it is the last 3 that show some of the coolest stuff.
2 Good Quality Vids
3 Low Quality Vids (but show the coolest features)
edit: If these next 3 videos don't work for you just follow the link at the top of the video, for some reason they appear to have issues when embedded.
Also here is a random gameplay vid (watch your volume on this one):