My iPod Touch's battery is not performming as well as it should. I've had it for a while. Is there such thing as a battery conditioner that might help get the battery performance better?
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)
Probably it's just getting old. Rechargable batteries wear out over time. About the best you can do is run the battery all the way down to 0%, such that it wont even turn on, and then charge it all the way back up to 100%, without unplugging it, leave it connected to the charger for several hours even after it's back to 100%. Repeat this a couple times, and see if it helps (no promises though).
Although this doesn't really answer your question so much, I thought I would add to what NJD said as it's important to understand where "conditioning" IS useful.
The only consumer batteries that really benefit from "conditioning" are lead-acid batteries (think: car starter, marine/RV, and motor scooter batteries.) Putting a lead-acid battery thru a reconditioning cycle can "de-sulfate" the plates in the battery giving it back some of its lost capacity.
NiMH and Li-Ion cells don't benefit from "conditioning". You'd just be putting your battery thru an extra deep discharge and charge cycle.
(Although, as NJD pointed out, doing this with a Li-ion battery can sometimes give a more accurate indication of actual run-time due to the recalibration of the circuitry that accompanies the Li-ion battery. It still doesn't improve the battery itself.)