An admin over at All4Android is a to be a tester for Android 2.1 on the Xperia X8. He notes that, there is usually two weeks of testing for the update and then a further week before it actually begins rolling out.
He says that testing will begin on Monday, so we should see the update rolled out in a little over three weeks. We’ve already heard previously that the update would be released before the end of the year, so it looks like things are on track for the Xperia X8 Android 2.1 release.
Source: All4Android