Easiest way, and looking at one of your previous post's you appear to have the latest CyanogenMod 4.2.8, would be thus.......
Buy a class 6 microsd card such as
Download the latest version of
Amon ra's Recovery stick it in the root of your sdcard, load up somethign like
Better Terminal Emulator and follow these instructions
Copy recovery-RA-sapphire-v1.5.2x.img to the root of your sdcard
start the terminal app
$su (not required if you have root already)
#mount -a
#flash_image recovery /sdcard/recovery-RA-sapphire-v1.5.2x.img
where x is put in the letter of the version you downloaded, if a Vodafone 32B Magic then it's G for Google branded phone.
This will flash you Amon Ra's improved version of the original Cyanogen 1.4 recovery most of us got when we rooted.
In this recovery you have menu items that allow for formatting your sdcard so you don't need a script like sdparted and adb (well it actually uses sdparted but you don't have to worry about doing the formatting manually.
I formatted my sdcard....
96mb swap
512mb ext4 (where cyanogenmod will put your apps)
FAT32 the rest of the card.
Simple.