A nosegrind is pretty much what it sounds like. During the grind, your front truck is on the rail, while your back truck is hovering above it. (see picture gallery)

1) Ollie up onto the rail, by any means possible eg: jump ramps, drops off of stuff, etc.

2) Make contact with your front truck and the rail, distributing your weight equaly on both the front and back finger, directly over the front truck.

3) Grind

4) Come out of the grind by either just riding off of the grinded object or in combination with a nollie shuv-it, nollie 360 flip or other nollie trick

5) Practice, practice, practice