Default Apps Installer 0.2.1 or Other - Help!

Hi Guys,

I just bought a new HTC Desire and want to get into installing new apps.

I came across the Apps Installer 0.2.1 and downloaded it but have no idea what to do with the files.

How do i get the app installed so I can start installing apk file. Where do I copy the files, etc.

Anyone else recommends anything else to use as an app installed.

Appreciate your help.

Thanks and P.S, I love my phone. Its amazing and I hate iPhone!