if your gonna do that you may aswell just download straight from the market,
BUT if you really must put them on your phone from computer,
what you can do is on your mobile go to the android market and look for a app called App Installer (i use it on my tattoo, so it does work)
than if you connect your phone to the computer via usb, make a folder called apps, put whatever apps you want in there from your computer,
disable the usb connection,
than open up the app installer app on your phone and it will automatically find the apps on your sd card and you can install them.
but whatever apps you do install make sure they are FREE ones ,as all DEVELOPER'S put in hard time and alot of work and effort to make these apps, so they definatley deserve the credit.