I agree with what everyone else has said about Handbrake or Roxio.
It depends on a couple of variables.
1. What format did you record them in originally (MPEG, m4v, TS, etc.)?
2. What kind of quality are you able to live with for playback?
3. Are you limited on what you can bring and if yes, are you bringing your external HDD?
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If you are bringing your external HDD, then store them all there and you're able to play them directly from the external HDD.
If you're not bringing the HDD, but you still want to back the files up, then copy them all over the external HDD. Then compress them one at a time via one of the aforementioned programs, with the destination folder being your "Movies" folder on your Mac HDD.
You can also compress them AND convert them to .m4v then store them in your iTunes library, if you wanted to transfer them to an iPod Touch, for more portability.
FYI - before you leave to serve our country, please do a backup of your system to the external HDD, with either TimeMachine or CarbonCopyCloner, or an online backup to something like Carbonite.com. That way, if you have any issue with the laptop not operating correctly, you can rest assured you have a backup!