I am trying to distribute my application to some people for testing. I have installed it on my Desire directly from eclipse and it works fine.
To create an APK-file,
I cannot install an apk build with "Export Unsigned Application Package" Android SDK feature, but i can install an apk browsing the bin directory of my project after the project buid. I put this apk on my sd on my HTC Wildfire phone, select it and the application install correctly. You need to allow your phone to install unsigned apk. Good Luck.