I know this may sound like a stupid questions, but..

[JoshPerkins]

What is virtual memory, and what is it's purposes?
I sometimes get a 'not enough virtual meory, creating more' icon sometimes and I was just wondering if it was anything to worry about?
Thanks in advance,
Josh.

[kwicky]

RAM (Random Access Memory) is part of the configuration of your computer and which you can also buy to extend the physical memory.
Virtual Memory is used by your computer for temporary storage on your hard disk and is used to run programs that need more memory than the RAM can provide.

[rojash]

I would guess that either you don't have much RAM, or that you run a lot of programs at once, or a mixture of both. As Kwicky says, Windows swaps stuff out to a disk file (virtual memory) when there is not enough physical RAM available to run your applications. As this is MUCH slower than RAM, your best course would be to add some more RAM.