Equity - Comments please

[DaRiverRat]

This is a repost from another board as I only had a couple responses I thought this might be a better forum...

I'm new to Omaha 8, and have heard people referring to 'equity'. Can someone please give me a definition and or a book to read on the topic?

Also, how does that apply to this situation:
O8
I have 8s 2s 4c Ad / heads up vs 8c 4d Ah Th - the board is qh 8d 4h 4s - I'm thinking good hand so I pot bet - according to twodimes.net it says my hand was only a EV of .562 - while I see how I can lose if a ten comes up 3 times, win low 16 times, we push 37 times - it just seems that it would be right to pressure the other player. How should I read a hand at .562? Is it .562/.438 = aprx 5/4 favorite?

Sorry for so many questions - but thanks for the thoughts.