i opened a thread a few months back when my gf faced the same problem as u:

http://forum.lowyat.net/index.php?showtopic=257294&hl=

basically, u'll have to read ur employment letter (unless u're still under probation, which means u can leave within 24 hrs notice). if ur employment letter says that u have to stay within ur notice period or give payment in lieu (compensation) to the company, then most probably u'll have to sacrifice ur salary to leave earlier.

but if u have the same case as my gf, which is that u have offered compensation but ur management refuse, then just leave immediately without notice. nothing much they can do to u.