How can I put sockets in my armor and weapon?

[Feryar]

If you want to add sockets to your equipment you will be able to do that after finishing an Act 5 quest.
http://www.battle.net/diablo2exp/quests/rewards.shtml

I've never heard of the armor + 5 gems cube recipe, but there is one recipe that requires 3 chipped gems and one sword which will give you a magic sword (blue item) with 3 sockets.