reducing file size - plz help...

[st-anger]

hi guys - i (again) need the help from the IT pros - u know, as i´m computer dork #1 in here - so i have recorded some vids with a camcorder and now have it on my disk, recorded it onto my PC with full .mpeg quality, so the vids are quite big now and i need them with less MB but in more or less the same quality so some kind of compression, this may be very easy again but i have absolutely NO clue how to do all this - any help would be much appreciated....THX in advance...