knocking sound from engine

[240sxHitman]

the other day after work around 12 or so i left and it was cold and i let it warm up for a few and drove off did a slight burnout but not a serious one, all of a sudden i hear a like i clicking of knocking sound coming from inside the engine and also im beginning to leak oil a little. my friend said that i spun a bearing. It happens when i drive and rev it slightly. It sounds if something might be loose. can anyone tell me what it is and if it is the bearing how going about to fix it. I personally wont but if i know what is to be done i will kind of get a feel of how much it will cost.

[s13sr20chris]

high or low pitch? fast or slow? single knock or double knocketa? top of engine or bottom?