Sites come and go... you should check out several and decide which ones you like. Some are very minimal, and others are extremely detailed.I'm intrigued. Do you know of any site like that in particular, or should I take the first one I google?There are dice - but they're rolled on a different site, you can specify any number of any kind of die (ie. roll 3d6 or 2d20 or whatever). The dice get automatically rolled, and the results are emailed to the GM/DM and the roller. It's possible to set up any number of pre-rolls, so people aren't constantly having to do this. Unless there's a glitch in the software, there is no possibility of cheating.
I'll make up some character sheets tomorrow evening after work (with unique TrekBBS rules pulled from multiple systems), give a set amount of build points each person must spend, make two threads (Rules/Character sheets and Game), and limit the game to a weekly event (Mon-Sun for those who work and a switching point if someone else want to be the GM). The Character thread will be a first come first serve basis. I'm making a Captain NPC for my game but whoever chooses Commander first is second in command, the Helmsman gets to roll for piloting (or the person who replaces him when he critically fails and his panel explodes), and so one and so forth. The Game thread will start off with the setting and characters will be in charge of moving the story. Characters who live (don't fight a Klingon if you have Body 1 and Brawl 1 and not expect to be impaled) get experience and can use their character again if we use the same setting (TOS week 1, TNG week 2, maybe 26th century week 3...).
I think that covers the basics. Anything else before I start making a system?
http://www.roll-dice-online.com/
http://rolz.org/
The above might give you a few ideas of what you're looking for. I found a lot that were only for d6 but if you need other kinds, those won't work.
This is the site recommended to me by a friend who's running an old-school AD&D game: http://invisiblecastle.com/ Just at first glance, it looks pretty decent.