What do you mean how do you make them? theres not really that much to them. if you apply a gradient you can double click the little preview bar in the blending options and edit the gradients and save them.
From personal experience, don't use gradients unless very,very basic. I find that creating the desired effect using multiple layers creates a more unique, individual touch, one the client is most times happy with
Gradients don't need to be for web2.0 websites if thats what you are implying. look at the talk freelance logo in the top left corner the pen and paint brush have multiple gradients. Without those gradients it would look very basic (or not as cool )