I've done this. I bought it from a company out of Florida. Cheapest I found and good quality.
Epoxy : Kleer Koat Table Top Epoxy. I called them to talk and make sure I ordered the correct amount. This site has the instructions on the link above. Read and read and then read again. Make sure you understand them, prior to mixing. You have a limited time to get it laid.
Pointers.....
#1 and most important! Make sure the epoxy is at least 75* before mixing it.. When its cold it will not mix together and you will have air bubbles, which you will not get out!
-Get a heat gun to pop any bubbles that form, but do not direct the heat to one spot to long, you will boil it and wreck it. Just pass over it like your using a rattle can. Its amazing how quickly it pops the bubbles.
-Do not rush the cure times, and follow the instructions to a T.
-I used 5 gallons to do mine, Make sure you dedicate a weekend or time to do this. Plan out the times If you let it go beyond the max cure time you will be waiting until its cured and having to sand it. Took me a full 2 days to do it.
-Protect anything you do not want epoxy on, especially if you plan on letting it flow over the edges.
Im sure there are more things, so if you have any questions send me a message. I'll post pics of my bar when I get home tonight