I have a universal Turtle Beach PX21 that works for PS3, 360, and PC. How do I get it to work for the Wii U?

I personally don't know of any USB headsets that work with the Wii U but what's the intent, regular game audio or just in-game chat?
If just regular game audio, plug it into a regular USB port and see what happens. USB is standard so it's down to whether the console's operating system will detect and use it.
If it's for in-game chat then that's going to be game-dependent as well.
I have a set of Tritons that I've yet to try as usb (which is for the in-game comms, game audio is separate) so if I have any joy, I'll post back.

After trying various search terms I finally found them - PC headset to smartphone adapter.

Amazon
http://www.amazon.com/gp/product/B002SK66OY/ref=pd_lpo_k2_dp_...

but for those of us in the Antipodes, eBay's probably the best bet.

http://www.ebay.com.au/itm/PC-Headset-to-Smart-phone-Adapter-...

Just be sure that the male end is 3.5mm (standard pc audio port size) or else you might end up with the 2.5mm (some smart-phones and audio players).

[edit] just ordered two from eBay [/edit]

Do I have to get a headset? I thought you could just use the mic on the GamePad...

I think it's game dependant, Kid... I prefer using a headset so the missus only hears me yelling

I saw some at target today and was really impressed. There are some legit Nintendo Licensed headsets. Very Nice Nintendo very nice!

Um, first of all, the PS 7.1 surround headsets are USB-only, not bluetooth (unless I'm missing a model). Also, they are virtual surround, obviously, not actual surround. However, they still work very nicely.

I've been using the Playstation PULSE Wireless Headset with my Wii U. This headset is primarily used over USB (and doesn't work that way on the Wii U). However, it also has 3.5mm jacks (both on the headset itself, and on the USB wireless adaptor). So you can connect the gamepad to either of these and use it that way.

Sound quality is really good, especially the bass, and the headset comes with several balancing pre-sets that you can cycle through.

Cool. Good to know. I haven't looked up any specs or reviews on those(the Pulse ones that I was saying, and you mentioned, too), but I just assumed they were better than you stated. I should have figured since those Pulse headsets are $100, which kills the $200-300 in terms of price. I would mainly be using the headsets for the surround(not a big fan of chat with random people). Well since Christmas is over, I'll probably be going to Best Buy soon to pick up a bad a$$ reciever that I will probably never have to replace, so I won't even need a surround sound headset. $20 or less headphones w/ mics are the way to go for now everyone, until a REAL headset come out.

does anyone know if there are any headsets that will double as headphones for any game i choose to play? I only have digital audio out on my tv and no headphone jack. Headphones on the gamepad work fine but only if i'm playing the game via the gamepad. I want to listen to my games in headphones as i play on the tv and not the gamepad. Is there anything that allows this?

Really? I was thinking in-game chat. I would have thought Nintendo was building in a standard framework for voice support this time around - aren't achievements the only "roll your own" aspect on Wii U?

If USB headsets aren't supported how are the Wii U headsets I've seen in shops connected - Bluetooth?

Just a note that almost every 'surround' headset out there is going to be 'virtual surround' (rather than hardware surround). From what I've heard, the few hardware surround headsets that you may come across, actually don't work as well as the virtual methods. Of course, nothing will replace a receiver (but do some reasearch there first, I've read there are some caveats).

Think of getting these http://www.newegg.com/Product/Product.aspx?Item=9SIA0PG0H35127

@Jellitoe
I totally want those!