What is a good amplifier for an electronic drum kit?

I have an Alesis DM5 electronic drum kit. What would be a good and cheap amplifier for me. I am currently using headphones but I want to record the music on my computer. How do I do this or what amplifier do I need?

Here are a couple to consider…

http://www.musiciansfriend.com/product/Roland-VDrums-Lite-PM01-Drum-Monitor?sku=449782

http://www.musiciansfriend.com/product/Simmons-Electronic-Drum-Set-Amplifier?sku=490070