Using old laptop as wireless router for MBP

Ok, not sure if this really makes sense, but i have just bought a macbook pro wich is my first mac and i love it.

My question tho is can i use my old laptop which will be connected to the net via an ethernat connection as a wireless router so that i can set up a wireless connection in the house for my macbook??

Thanks

Short answer, Yes.

Can you tell us a bit more about the old Laptop? Brand? Model? Does it have built in WiFi besides the RJ45 ethernet port? Which OS is installed? XP? Vista? 7?

I have done this very thing many times using both a Mac or a Windows machine as the router. Only thing I forget is if say XP Home has that option or not. All my XP's in my house are Pro. Should work though even in Home. BTW, in Windows it's called Internet Connection Sharing (ICS).

Tell us a bit more about the Windows Notebook and it's OS so we can better help.

Ok Thanks

so its a dell inspiron 1525, It has a built in WiFi and is running XP Pro

Do you need help with the settings in Windows for ICS?

Yes, please, if you could.
I've managed to set up a wireless connection between the two notebooks but i can't seem to get the internet sharing option to work. I've enabled it in the wireless and LAN network settings on the XP machine but i'm not having any joy with it.