I have most of the info...

If you have a router its as simple as connecting an ethernet cable from the router to your xbox 360 :)

Then just going to the connection settings on the xbox 360 and setting everything as Automatic it should work with no problems

If not what connection method are you using ? Internet connection sharing/ Wireless ?

I have the wireless adapter the only thing is that it just won't connect even though I've put in all the info.

Have you got it sorted yet ? What fails when you test the connection as you have to enter the WEP key of the router you want to connect to on the 360

Where do I put the wep key

On the network settings section of the xbox 360 dashboard it should say

WEP :

So you enter the code on your router in that box :)

It doesn't :(

It does.. the top one unless your connection is not secure... even then it should automatically connect

System > Network Settings > Edit Settings > bottom tab > Click on the Wireless Connection shown (May ask for wep at this point) > Select Test Xbox live Connection

It won't let me use wireless connection