www.knittinghelp.com has quicktime of damn near everything.

But to explain it fast--for the cables I'm doing right now, you just slip two stitches onto another needle and let it hang behind, knit two stitches, go back and knit the ones hanging out, purl one, repeat until end of row. And I only do it every sixth row when I'm in pattern for the cables.

I can show you tomorrow!