Are you exporting as cocoonjs? This is the option I tend to use. It will package your app up into a .zip file which you can load from your computer to your phones sd card.
Then you just need to download the cocoonjs launcher app from the android app store. Once you have this installed you can run your app through it, and viola!
If you're using phonegap, you can export as HTML5, upload this to the phonegap website. They will create several different versions for you. And you can upload these onto your phone via a QR code reader. I haven't use phonegap for a while (so not sure if things have changed), but this used to work for me.
Edit: both these options (and more), are available when you select export project from the file menu.
Good luck :)