If you mean will any songs you delete from your iPod or an iTunes playlist you have created also be deleted from your iTunes library, the answer is no.
what i mean is ,every time i put a album on my ipod it goes onto !!! on-the go and there is about 6 gig of songs on there . So what i was afraid of is if i delete the on-the go songs would my albums be deletes .
Is 'On The Go' a playlist you have created/a predefined iTunes playilist? (showing under your Library on the left hand side of the iTunes window).
If so, the songs in there should also be in your Library. Check to see. If they are, you can delete one or all of the songs in the 'On The Go' playlist.