Don't count on it. APPS2SD is the function that lets you move some of the data to an external storage.
However, only part of the program is moved. and only apps that are coded for it will work with apps2sd. I'm guessing only the data files (i.e. game levels, sound effects, etc.) are moved, and the actual program files remain. Which would make apps2sd barely useful if your apps are mostly utilities. Facebook, photoshop, yahoo messenger, for example, can't be moved.
Lemme see what i have on my archos. Just as a sample, i'll list the apps starting with 'A'
Android Comic Viewer
-646KB
-Does not support apps2sd
Adobe Flash Player 10.1
-10.81MB
-Does not support apps2sd
Aldiko
-5.68MB
-Does not support apps2sd
AndroZIP
-0.8MB
-430KB remaining after apps2sd
Angry Birds
-16.02MB
-1.88MB remaining after apps2sd
AppsLib
-3.31MB
-Does not support apps2sd
Better than nothing.