I don't know if this is scientifically valid--I'm not enough of an expert--but it looks plausible--certainly sufficient for gaming. Here's a well thought out tide-locked world which keeps in mind the fact that orbits are usually not circular.
http://www.worlddreambank.org/L/LIB.HTM
http://www.worlddreambank.org/P/PLANETS.HTM has a lot of neat concepts :)