hey i hope it helps but you need the following
1) PC with dvd drive and its needed just for preping of the pen drive. it dosn'nt format ur HDD
2) Atleast a 8 gb pen drive
3) most imp a Kalaway intel/amd 10.5 DVD. if you dont get it plz let me know i will try 2 send u a link as i don't seem to remeber it at the moment. download it first and write it to a dvd. then you need to download some more
4)Now u need to also download a retail copy of 10.6 snow leopard. plz obtain an original copy from apple store for legal purposes. if you want you may download a copy via torrents but only for trial.
5) Download Netbookbootmaker app from melkort etc,
6) Boot from 10.5 kalaway DVD on the pc and go into disk utility

from here on the other tutorials available on this site on how to restore a sl dmg to usb should be referred. any doubts or queries plz feel free to ask. ve a great apple exp