LimeWire Pro is virtually identical to the free version except that it doesn't include any advertising (or spyware).

It is as easy to install as the free version (though you may need to go to a bit of effort to uninstall the advertising that comes with the free version - get a copy of adaware from lavasoft).

It is easy to download.

You'll probably need a credit card to purchase it ($9.50). I used paypal but I believe there is now an alternative to this (Paypal may not need a credit card - maybe).

Mark