All Android devices upgrade by this method, individual makes use slightly different button combinations to instigate the upgrade and they also call the upgrade file by slightly different names but the procedure is identical.
You can find experimental roms for many phones on dedicated sites (Google to find them). I recently upgraded my Eclair (2.1) to Gingerbread (2.3) by using an experimental ROM. It works well and is certainly faster than 2.1 or 2.2 but the jump to 2.2 is worthwhile.
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