It's all right here man.
http://www.battle.net/diablo2exp/ite...teditems.shtml
If you're too lazy to sort thru it, here's what's important.
At ilvls 1-30, there's a 40% chance of 1 affix and a 20% chance each of 2, 3 or 4 affixes.
At ilvls 31-50, there's a 60% chance of 2 affixes and a 20% chance each of 3 or 4 affixes.
At ilvls 51-70, there's an 80% chance of 3 affixes and a 20% chance of 4 affixes.
At ilvls 71+, there's a 100% chance of 4 affixes.
The ilvl of a Crafted Item is equal to half the level of the crafting character (rounded down) plus half the ilvl of the input item (rounded down). Put another way: ilvl = int(.5 * clvl) + int(.5 * ilvl)
It's also worth noting that the ilvl, the quality and the properties of the jewel are completely irrelevant and don't affect the outcome at all.
All taken from that exact page on Arreat Summit.