Google - which has been experimenting quite a bit with a look-up-table based transliteration scheme for Kannada, has now integrated the feature into its popular free web-based email service - Gmail. Of course, this feature has been on Orkut and Blogger for a while now.
This means you don't need to run any extra software in order to type in Kannada on Gmail.
Of course, Google's database of words is not complete, but given the processing power that's getting packed into computers today and how big today's databases can be, this is one possible solution to the problem of input-methods for Kannada data entry. Of course, giving users the ability to add words to the database is a wonderful idea which Google has successfully implemented.
There are notable differences between Kannada input-method editors such as Baraha, Lookeys, Lipikaar, SCIM (for Linux), Nudi, etc, and of course Google's database-heavy transliteration scheme, but it's good that all of them atleast use Unicode. Of course, it's a different story whether Unicode - the way it's defined right now - is the best code for Kannada or not.