Im using windows xp sp2. and I want to emulate ubuntu 10.04 using virtualbox, can I make use of seamless mode in here? I've already installed the guest additions.
You can have both XP and Linux on the same disk, by using Linux as an application within Windows. This way, you don't disturb XP at all.
I suggest the Wubi linux distribution, since it's a variant of the very popular and easy to use Ubuntu Linux:
Wubi -- an officially supported Ubuntu installer for Windows