I have that laptop, dunno about the modem. I have the BCM V.92 56K, apparently I heard its a win-modem. I've had no need to try and test it yet, but its on my to-do list (I can VPN into my campus network). My setup:
Distro
Slackware 10.0
Kernel
linux-2.6.10 (no patches)
Window Manager
Fluxbox-0.9.11
Display
1400x1050
Sound
ALSA, emulating OSS API
Network Controller
Yes, with module
tg3 loaded
Wireless
Yes, with ipw2100 loaded as module
USB Key Support
mount -t vfat /dev/sda1 /mnt/usb works for me
Thats about all I've done so far, I still need to do the following:
CD-RW/DVD
Haven't read much about this, its on my very near future to-do list
MODEM
I'm sure you dont care about any of this post, seeing as how all you want to know about is the modem. Unfortunately I haven't had a chance to test this yet, and it is pretty low on my priority list
PCMCIA 802.11g D-Link Card
I want to get this baby working soon, 54Mbp/s w00t!
I've done more stuff that I can't really think of right now. I really love this laptop, I can't wait till I "finish" it.