hiss question---

sometimes when u sample from vinyl and older music,
some of the music has some hiss in it do to the way it was recorded.
i can really hear it when i put it on the mpc.

what is the best way to clean of the sound?
noise gate or limiter maybe?

A noise gate could be set to clean up spaces between beats in a break ..... but you could also do this by silencing those bits of the sample. Computer sample editors usually have features for cleaning up samples like this. Otherwise careful use of EQ or a low pass filter should help.

A limiter won't help you here.

Sound Forge has a removal hiss preset. It works pretty fine, but this is not gonna be a miracle.

If you want miracles, Waves restauration bundle is very good. It's about the same price as a Russian bride on E-bay though.....

Voxengo redunoise is not too bad either. There's a demo on their website:
http://www.voxengo.com/redunoise/