At the moment, Android does not support any virtual keyboard, but that may soon change. It turns out that the Android roadmap has somethign in store for us that should be released in Q1 of 2009. Here are some of the details from the site:
This feature will enable support for input methods other than physical keyboards, for example soft keyboards. IMF will also enable application developers to provide IME (see below) applications based on the framework.
Input method engines (IME)
IME will support soft keyboards, a dictionary of suggestions, and a suggestion algorithm. The Android platform may contain few reference IMEs, and developers can provide IME applications through the Android Market.