Man I suck at theory. I'm supposed to play with some guys and they want to play a song that is supposedly played in (Bb) and they want to do it in A. The very beginning of a song starts out like this:

---------------------
---8---8-------------
-----8---------------
---------------------

If I wanted to play this same song in A where would my starting point be instead of the 8?

You move everything down a 1/2 step, or one fret down.

7

What about:

--------------
-----0--------
-------0-3----
-0-0----------

And they want to play it in "Drop D". what does that mean?

welcome to the wonderful world of altered tuning;)
drop D means the low E string is tuned down a whole step to D. this is mainly of use for guitarists as it lets them do powerchord riffs more easily. so the 12th fret on your bottom string will sound the same note as the open D string. from low to high, your bass will be DADG.
good luck!

You may not need to retune at all, even if the guitarists have.

And they want to play it in "Drop D". what does that mean?
I would find out what *they* mean. Some guitarists say drop D when they only drop the low E string down to D as mentioned above. Bass players almost always mean this when they say drop D. Some guitarists say drop D when they tune down a full tone (i.e. D G C F for bass).

And some guitarists say drop D when they play open D :rollno: Open D is D A D F# A D for guitar. I have also heard of open D called slack D tuning since you only decrease, or keep constant, the tension on the strings.

If they are tuning down a full tone, you might want to also unless you are really good at transposing. For the other cases, I would only tune down if I really needed the low D.