[jQuery] Tool used for compress jquery.js, help!!

[jQuery] Tool used for compress jquery.js, help!!

I'm trying include json plugin published by Michael Geary y the same file .js then I've downloaded all jquery sources (base, fx,minifx,events,ajax) plus json plugin and paste in the same document. I tried compress by <a href="http://packet.net">
packet.net</a> and other js compression tools but the result file don't work.
I only can compress a bit with jsmin and the result file work correctly but it's too heavy yet (20+kB) :-(
what is the tool used for compress jquery downloaded from the official web?
_______________________________________________
jQuery mailing list
discuss@jquery.com
http://jquery.com/discuss/