We've seen the HTC Sync app version 3.0.5387 being released not that long ago only for the HTC Wildfire, with HTC's promise to release the Sync app for other Android devices too.
Looks like a newer version of HTC Sync, namely 3.0.5422 is going to be released soon as it has just appeared on HTC's Support page but the download links are not (yet) working, so make sure to check back to the page soon! According to the description, the software is suitable for the HTC Aria, HTC Wildfire, HTC Desire, HTC Legend and HTC Hero devices running Android 2.1 Eclair and above. Another note is that "this update is applicable for APAC & EU HTC Hero (Android 2.1) , HTC Legend, HTC Desire, HTC Wildfire, HTC Aria. (This update is not intended for use by North American customers)".
As far as installation is concerned, download the file to your computer and run it to install from there. After installation you can connect your Android device to the app and start synching. Besides synching Outlook contacts and calendar or Outlook Express contacts and the bookmarks of web browser between your computer and your phone, it also lets you install third-party Android applications on the phone, and bring your photos, videos, documents, songs, and playlists to your phone.
EDIT: Turns out you can download the HTC Sync app from here!