Is there a battery conditioner for an iPod touch?
The iPod Touch has a lithium-ion battery, which really does not need to be conditioned like the older battery technologies did.

In fact, completely discharging a lithium-ion battery too often can severely shorten its life, so I wouldn't recommend doing a full discharge too often. And I wouldn't recommend using something that goes outside the normal voltage range of the battery either.

Discharging occasionally, perhaps once every 30 charges, can help to calibrate the battery so that it can given a better indication of run-time.

Apple recommends discharging completely about once a month.

Lithium-ion has a limited life-span anyway, typically 300-500 cycles; and they degrade over time too. How quickly they degrade depends on how hot they've been stored.

(See Battery University for more information on this)