XP Desktop to Vista Laptop for playing music.

I'm asking what steps I have to take to connect a Vista Laptop to an XP desktop for the purpose of playing music using the laptop.

I researched some cables, and I'm not sure which to use, or which is better, or even if, and how I could achieve this.

 

You first have to set up a network. Then you can share things such as music, over that network. Have a look here for guidance on networking:

http://www.microsoft.com/windowsxp/using/networking/default.mspx

Once you have your network, you then need to decide how you want to share your music: do you just want to be able to share your music files (mp3 files for example) or do you want to stream (broadcast) them?