creative modem are WINmodem!
the link is here for ess modems..
for beginging from the very scratch, check out linmodems.org.
linux does have troubles but with closed standards, anyways you might find a generic driver for your modem.
i have a Creative Modem Blaster V.90 PCI DI5655. it did not work with fedora! i tried a lot to find drivers for this modem . i did find one but that was for kernel 2.2 i don remember whether it worked successfully with kernel 2.4.
hope that helps.