it does depend on the amount of music you have as to what the easiest way would be.
if you only have a fairly small amount then burn them onto CD(s) or use a USB memory stick and copy them across that way
If you have a substantial collection then as above says then external hard drive is probably the easiest, but unless you already own one isn't a cheap option. If both computers have a network card in them then a CAT5 crossover cable (available fairly cheaply) would enable you to network the two computers together directly with no additional hardware then you could copy your tunes directly from one to the other.
But as said it really does depend on the amount of music you have
I have about 8GB worth of music on there.
It's not possible to use an external HD as I can't do a drag and drop sort of thing with the Itunes Icon on the desktop.
Do I have to download the programm again on my new laptop and then re-import the lot?