I saw this on the HTC forums, but since I'm new to Android (I don't yet have my Aria), I'm not sure if it's legit or not...(
http://community.htc.com/na/htc-forums/android/f/96/t/8213.aspx)
"it's starting to roll out via OTA in South East Asia... keep a look out for a notification on your phone we could be getting it soon here in the states....here is the post from HTC SEA website
http://www.htc.com/sea/support.aspx Update – HTC Aria (Android 2.2) Firmware Over The Air (FOTA) update
Your phone will receive a notification of FOTA update when it is made available. Simply press OK to accept the update via a data connection such as Wi-Fi or GPRS/3G. After installing the update, you can confirm a successful update by confirming the Build number (From the Home Screen go to MENU> Settings> About Phone> Software Information> Build number). The new Build number after the update will be 2.37.708.5. Update: Android 2.2 and HTC Sense update. Note：Please back up your data first before upgrading your phone. We recommend using a free Wi-Fi hotspot or an unlimited data plan to apply this update. If not, standard data connection charges may apply. For any questions, please contact us at
http://www.htc.com/www/CA_Hotline.aspx 
