The good folks over at XDA-Developers have developed an automatic call recording utility that will automatically record your incoming and outgoing call conversations on your Windows Phone. This should work on most HTC
phones, but you can try it out and let us know if it works on your device.
Go to
XDA-Developers to
download and install the cab onto your device.
For legal reasons, be sure to obtain permission before recording and using this app and alert the other party that the call is recorded.
Edit: CAB Included!