WARNING: This will completely and permanently delete everything on your SD card. Make sure you backup what you want to save onto your computer. (Alternately you can try to resize your fat32 partition instead of deleting it, but I'm not covering that here.)
Turn off the phone, pop out the SD card, put it in a card reader and plug that into your linux machine.
[Edit] Alternately, you can just keep your card in your phone, reboot into Recovery, plug your phone into your computer with a USB cable, and "mount USB" in Recovery.
Start Gparted. Choose your SD card as the "device" you will be working on in the upper right corner dropdown menu.
"Unmount" the card so you can partition it, and delete all your previous partitions. You'll end up with a blank card:
Screenshot__dev_sdc___GParted.png 29.88KB 278 downloads
Add three new primary partitions: fat32, ext2, linux-swap.
Screenshot_Create_new_Partition.png 32.36KB 288 downloads Screenshot_Create_new_Partition_1.png 31.67KB 215 downloads Screenshot_Create_new_Partition_2.png 31.99KB 185 downloads
Screenshot__dev_sdc___GParted_1.png 63.57KB 182 downloads Screenshot__dev_sdc___GParted_2.png 39.98KB 172 downloads
"Safely remove" the card and you should be good to go.
Edited by twrock, 12 November 2010 - 01:21 AM.