Fistful, you'll find the Ubuntu installation to be pretty easy. Dual-boot is no problem, Ubuntu uses the "Grub" bootloader to present you with an OS-selection screen at boot time. Until a couple of days ago, I had Ubuntu, Vista, and 7 all on the same machine!
The new Ubuntu release came out on the 23rd, by the way, and it's an improvement. Works great on netbooks, has (unlike previous versions) drivers for the oddball wireless chips, like Atheros.
I'd be glad to help if you run into any trouble.
A.