Unfortunately, I wasn't able to keep my phone number when I switched from AT&T to Sprint in order to use an EVO and now WaveSecure tells me I'm screwed. I don't get to keep my 'lifetime' subscription even though I'm no longer using the old phone. I spent way too long on their site trying to figure out how to transfer the info, and then emailed them. They told me "This offer does not allow users to change their phones".
I'm pretty displeased about this.
So, I've downloaded iTag instead. I'm mostly looking for something to help me find my phone when I lose it. I think iTag will work for that and so far, they're free.