This yesterday I was watching tv and there I came to know a vista feature Ready to boost its a feature which temorarily increase your ram from a removable media like Pen drives.
But pen drive should be ready for ready to boost so only latest pen drives having sticker(ready to boost)  will be helpful.
How it works?
when you insert the pen drive there will be 2 options 1)media storage 2)ready to boost.
use ready to boost so temporarily RAM will be increased.
also it is tested that if you have 4 gb pen drive it will increase ram to appx. 1 gb.
that is only 25 to 50% have been used in tests posted elsewhere.

Nice information you shared Kammy, I am moving it to "Computer Article Section" as TIP.

also be sure it is ready for ready to ram boost and confirm it from shopkeeper.

maximum upgradation is 4gb.

no windows xp don't include suchan inbuilt feature but it may be possible if some software developers work on it.

yrah here,s the link for it for our members.
http://www.eboostr.com/

thanks
I took it to the extent of having vesta with new pen drive.

Absolutely .. having more physical RAM is the best solution, however, if you have a Flash drive then why not use it too altogether But if you have really plenty of RAM then no need at all.