dual boot '98 & XP

I am currently running '98 and would like to install XP. A couple of questions:

Can I keep my current instalation of '98 or do I have to reinstall it?

What is the recommended partition size for XP?

If I use the same program on each operating system, do I have to install a copy into each partition?

I want to slowly migrate mostly to XP and use 98 only for some games. At some time in the future can I change drive letters to make XP my OS at start up since it would be on drive D: when I install it?

Is it a good idea to use a 3rd party multi boot program? I had a bad experience in the past with System Commander which locked my hard drive with some password crap.


That's a start. Probably more questions later.

Thanks,

Rishi