Is it possible to use Prey on a non-phone device? This answer to a question asked earlier today reminded me that I had been wanting to check out Prey because I had heard some good things about it. I ended up installing it and creating an account, but it appears you can only activate Prey on a lost device via an SMS message. Their original announcement for the Android version notes this, and it looks like things haven't changed (insofar as I can tell, anyway).

This is fine for my EVO, but I also have a Motorola Xoom and I'm not sure how it would work in this case. Also of note: I don't have a data plan on the Xoom, I just use it for wifi. It is a 3G version because I wanted to have the option of possibly adding a data plan later, but it has never been authenticated on Verizon's network.

The Xoom is supported and I can install Prey from the Market just fine, but is there any way for me to activate Prey if my Xoom - or any device that can't receive an SMS - was ever lost or stolen?
It doesn't look like there's an alternative to SMS activation just yet. Here's what they say on the Prey blog (emphasis mine):


  Prey for Android works the same way as it does in Portables and
  Desktops. The only difference is that there’s no standalone mode
  (yet), and the activation is not done via the Control Panel, but
  by sending an SMS to your phone with any message you want.


As this is currently meant for phones, if you have no data plan on a device, it cannot recieve an SMS and therefore cannot activate Prey remotely.

The good news is that it seems like standalone mode is being introduced in newer versions post v0.51, and only on Android 2.2 and above (no issue in the case of you Xoom)