Sony Ericsson just posted it on their Facebook page that Xperia X10 owners will soon be recieving an update. The details are not out yet, but it is not Android 2.1 or 2.2 update, so nothing really to get happy happy, but it will contain some bug fixes and performance improvement stuff.
From SE About the update:
When the new software is available, you will receive a message in the notification bar of your X10. The easiest way to get the new software is to accept this update – you can use your mobile network or a WiFi connection for the download. Alternatively, you can use PC Companion (click button below).
New features include:
Free backup and restore application for your contacts, messages, bookmarks, settings etc.
Improved usability of camera, media player etc.
Improved overall phone performance.
PlayNow, with premium apps and games available in selected markets.