You might do a search. Conversions have been covered at length on the COW. Methods will vary depending on what tools you have access to, what budget you have, etc...
The best way, but more expensive why is to take the tape to a dub house that specializes in standards conversion. They have dedicated hardware that will be able to accomplish this better than other methods. They'll give you a tape that is in your standard (PAL) which can then be edited as usual. If your final material is going to broadcast, this is your best bet.
If you budget is to light to be able to afford that, there are some software packages that might be better than others at doing standards conversion. Canopus Procoder on the PC side does an excellent job at NTSC/PAL (and vice versa) conversions. If you can find someone you know that has it, that might solve your problem.
Like I said, this has been covered at length, do a search on the COW, find out what will work for you with what you have available.
If you want to get a god conversion NTSC to PAL with Compressor, you must set the "Frame control" to CUSTOM.
I would recomend you not to "resize" your clips. What I mean is to make a PAL movie but 720x480 (or 486). The process will be easier (and mostly faster) for Compressor to do it. You can resize in FC, although resizing your Image (in FC or Compressor) will make loos some quality because must to be enlarged from 480 to 576.
Any way in the Compressor Inspector, set the "Retaiming Control" to "Better: Motion compensated.
Whichever is the system you use, the image will look a bit "jumpy", because your throwing away images (5 per second).