I don't know about the others, but I'm also doing what you're currently doing: starting as a fighter, then dualing over to a cleric in BG2. Sadly, I can no longer play BG1, as one of my cd's for the game is broken. So I've just had to settle with recreating my character in BG2, giving the character the same class, and similar stats to, what I would have given the character in BG (of course, making sure I take into account the fact that I'm going to dual class to a cleric, and so not only have the stats I want for a fighter, but also a cleric). I'm actually playing through for the second time (not including my failed attempts) with this concept. What I've been doing is dual classing over once my fighter got to level 8. At what level you dual class, of course, is your own choice. I have to say, though, the weapon restrictions can be a pain, but there are still quite a few of cleric-friendly weapons that are good.
I've enjoyed playing through with my fighter/cleric. (Actually, it's the only character I've gotten all the way through the game with, and it seems to be the only character I can do so with; my other characters never last long. Though, with each run-through I find I tend to make some change or other to the character; so far my current game hasn't been the case)
And galtzaiLe, if it makes you feel better, you do know something that I don't: TuTu. I have never used it (don't think I have, anyways), and I'm not even too sure what it is.

(I don't really need an explanation - it would take up space on this thread, and is a little off-topic; I can always just do a search on it)