Deleting unwanted old apps

im sorry but i dont under stand your situation

To delete apps from itunes and ipod: Delete the apps from itunes, then sync.

To delete from ipod and not itunes: Go to the apps tab, deselect the app, then sync.

http://manuals.info.apple.com/enUS/iPod_touch_iOS4_UserGuide.pdf

You can transfer itunes purchases ( including apps): Without syncing: File>Transfer Purchases

If you want to delete everything off your ipod but keep it on your mac follow these steps.
1.Sync your ipod with itunes to back it up.
2.In Itunes create a new playlist and title it 'none'.
3.Do not put anything in that playlist.
4.You will then sync your ipod again with itunes, but first you must edit some settings.
5.Go into your ipod syncing settings. Go into music sync it with the 'none' playlist.
6.Repeat step 5 except for apps and videos.
7.Sync it and it will sync your ipod with nothing and you should have nothing on your ipod.
Hopefully this is the answer you were looking for your question was worded strange.

The go to Apps in your library and delete them all, then connect ipod, do not sync, click File>Transfer Purcahses

Here is how to transfer app (and other iTunes purchases) to you computer:
http://support.apple.com/kb/HT1848