http://www.youtube.com/watch?v=niHvQ-P00gA

Here we go a good video of rod knock. They actually sound pretty similar only the lifter tick sounds a little more crisp and the rod knock is more of a clunk.

If you have a spun bearing or rod knock it will sound like that... but you would notice a huge difference in how it drives... and if it hasnt blown yet and your still driving it then its not a rod or bearing lol.

This is what a spin crank bearing sounds like... although i hate to admit it sounds alot like your case ... but i still dont think its this if your engine apears to be running normally

http://www.youtube.com/watch?v=ycM2rayUbvk