Macros live in workbooks. So you shouldn't have any trouble transferring the
macros to the new version of excel.
But the question that remains will be "do your macros run as intended in xl2010?".
Without knowing anything about your macros, I'm gonna guess that you won't have
any significant problem.
But the only way you'll know for sure is to test them using xl2010.
Maybe you can ask your boss to be the first person to get xl2010 (on a separate
pc) or installed on a virtual pc or even installed on the same pc (keeping
xl2003 alive and kicking).
Then you'll be able to test all the functions of not just your macros, but the
other workbooks you (and your co-workers) rely on.
If you have trouble, you may be able to ease the pain for others by fixing the
macro or talking to the developers of the other workbooks so that they can be
working when the rest of your team cuts over.
If I were your boss, I don't think I'd want to go into a situation with my eyes
closed where mission-critical tools are broken.