to format your drive for Linux use:
This is using "Slackware" the distro of Linux I happen to use.
boot from CD or floppy: Following commands are all done from a command line and should work on command line based Linux install. All are with the quotes ommited.
cfdisk /dev/hda <~assuming I'm installing to my first hard drive.
follow the prompts to re-create my partitions and then write the partition table.
For reference in CFDisk and Linux FDisk Linux Native is 82 and Linux Swap is 83 (I might have those reveresed)
once back at a prompt I issue the following command. Again assuming I want to format my first partition on my primary hard disk
mke2fs /dev/hda1
<random stuff scrolls by>
done...
Thats all there really is to it. If anyone has questions that are specific to a distro let me know and I'll do my best to help.
Redhat, Mandrake,Suse all have partitioning GUI tools if I recall correctly.