on my Ibanez by a shop, and I just went by today to pick it up. I've heard how easy it is to do it on your own, but I really didn't wanna mess anything up, and it was only an extra five bucks onto the setup cost. When I got it back, I was playing around, and my Edge III was effectively hardtailed. I took off the back plate to see what the guy did, and he wedge a dice between the wood and the end of the trem. My first though was "Wow, that's pretty ghetto!" And I'm afraid that this won't hold. Is this gonna be a permanent fix, or at least for a really long time?
Edge III is what I had on my Ibanez RG350 (very recently swapped out for a 1986 Jackson JT6 because i find it to be tonally better) and I had about £0.32 of change holding the block in the middle and it hadn't moved whatsoever in the 3 and a half months I'd had it set up like that (and this guitar had been 10 miles each way to college 3 days a week on a moped).

So yeah, a dice will be fine. He'll have set it so the tension isn't enough to break the dice or it'd have happened by now.
It'll have very slightly more tension than the springs / strings (the difference will be the force on the dice) and being as it's solid plastic it won't give way easily.
Thanks Bigsteve. One more question, is it gonna effect it if I tune down at all? I'm thinking nothing more than Drop D, or Drop Db.
You should be able to drop to what ever you want. The trem should not move if blocked. I would suggest that you make a wooden block that fits the trem better than a dice.