I use Ubuntu 10.10 amd64 and inside virtual box i use xp serice pack 2. I installed sql server 2008 but unable to install Visual Studio 2010 because it requires serice pack 3. Is there a quick way to upgrade service pack 2 to 3?
What do you mean, "a quick way"?
There's 'quick' in the sense of 'no effort' - switch automatic updates on and leave the VM connected to the internet. Eventually, it will have downloaded the service pack and installed it, and will then ask for a reboot.
Or, download XP SP3 yourself from Windows Update (or just Google 'XP SP3 download') as has been suggested, run the installer, and allow it to reboot at the end. It doesn't take very long to run.