Do you mean remixes? A white label is any pre-release tune that hasn't been signed up to a label yet.
It's very hard to do a remix if you just have an MP3 of the original track, because you can rarely get clean cuts from it. There isn't really any specific way to go about it either, make the track in your own style, but don't lose sight of the original.
If you want to get into remixing, some sites run competitions where you download all the samples you need then send them your finished mix for judging.
www.intermusic.com run these competitions occasionally and there was a thread somewhere with a link to a "fatboy slim - star 69" remix competition....
Some good software:

Cool Edit Pro
Fruityloops
Reason

Hope that helps

LaterZ

U will probably need some decent samples to get going with (unless u got reason.. then u just make em urself...) check these links for some half decent percussion and stuff:

http://members.tripod.com/~NIKKO5/samplenav/
http://hem.passagen.se/lej97/kalava/
http://spec.ch.man.ac.uk/~ashley/drums.html

Peace

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MUGGETS

Another site which is ok is www.samplenet.co.uk this site doesnt really focus on techno trance scene but there might be some things in there u might like! be sure to check it out!
=)