Install Error "for security, your phone is set to block installation of..."

Are you getting this error?

"For security, your phone is set to block installation of applications not obtained from the android market."

If so, you are most certainly an AT&T customer. There are two ways to get around this. The first is to simply download Mobile Merchant Pro from the Android Market. This is fine, but if you want to download applications from the Amazon store as well, you'll need to request an update be pushed to your phone. This can be done is just moments. What the update will do is to add a setting in your application settings that lets you download applications from "Untrusted Sources." "Untrusted" being anything other than the Android Market place.