too man y questions man. Firstly sampling is taking a loop or a sound from another song. Good programs to sample with are based on your preferences. If u prefer a loops based program, Acid Pro is the one to use. It allows you to beatmap the song you want to sample from so that yo can figure out the tempo and the when you change the master tempo the tempo of the track also chnges. this is good for when you are mixing two different loops. It also has a chopper so you can take different bits and pieces of the song you want to sample and arrange it in your own way.
Soundforge is a program that u can use in conjunction with Acid Pro for dead on accuracy when sampling the part you want.
Slicing is pretty much chopping. There could be more to explain.
a channel is one track in a multitrack software. for example you have a bass line drum line and melody in your song they can all be on three different channels. This makes it easier for editing and FX automation etc.
a good temp to work with depends on the type of beat you want to make. more mello beats are good at 80bpm to 85 maybe 90. 90bpm to 100 are good for your typical beats.
there are two types of samples, one shots, and loops. Loops you can get from other songs and same with one shots. loops a bar or more that is made to repeat seamlessly ( i think thats the right word) and s=one shots are exactly what ht ename says one note or shot of a particular instrument, or whatever. where you get these
www.Loops.net and other tracks. the good old stuff
the best beats makers are the ones that you work the best with. Something that u like and that can get the job done.
as far as techniques go everyone has their own