I've never actually finished a cross-stitch. But I know how to do them! They're really fun. I always run out of string or lose interest or something, though.
Hehe. Yeah. Those two up there? I've been working on them for *years*. I do some work on them for awhile, then something else gets my attention, and I set it aside for a few months, then I'll be cleaning or something and find it and pick it up again.
Run out of string? Just go down to a fabric/craft store (or Wal-Mart, they've got it too) and pick up some DMC. They're actually pretty cheap.