I have been searching Google and forums for a long time now, and I can't find instructions on how to install downloaded App Store apps (not things through Cydia) on my jailbroken iPhone. All of the searches come up with things like AppTapp which were for much older versions of the iPhone software. Can anyone help me out? I'm running MacOSX.
Do you mean cracked *wink wink* apps? If so then you'll need to change a file (mobileinstallation) on your iphone. A guide is here. Also check youtube, lost of vids on how to do it.