Depending on your distro, but generally as sudo or root do:
Then put in what you want to run:
# m h dom mon dow command
00 02 * * * "apt-get update"
That runs at 2 mins past midnight (or 00:02), calls apt-get update to do it's thang. You would put in the full path to your script.
Why would you want to create a terminal session for a background job anyway? Regardless, if you have aterm installed you can do:
aterm -e /path/to/command
You might want to check the switch, but I think it's the -e to call an interactive terminal.