You can assuming you have the appropriate data connection and an app like TubeMate

I don't believe you can directly connect the phone to an external hard drive for extra storage. If you need more space the only option is to get a bigger sdcard.

particularly virgin mobile beyond talk plan phones:
Samsung intercept android 2.2
Blackberry curve 8530
Lg optimus slider android 2.3
Lg optimus v android 2.2
Motorolla triumph android 2.2

Can they download things from the internet like videos, mp3, and files so I can transfer them from the phone to a computer with usb or whatever? Youtube videos need 'realplayer' downloaded to rip, so can i install a program like realplayer to the phone and have it rip the video to save it?
Can they connect to an external hardrive like through usb or whater wire needed in case the files downloaded are too big for the phones memory capacity?

thanks