How to run Thunderbird 2.0.0.24 under Ubuntu 10.10

[don fisher]

I have found that version 3 of Thunderbird consumes about 50% of my CPU, 
as show by "TOP -S". Thunderbird 2.0.0.24 uses almost none. I cannot 
find the older version under "ALL" of Synaptic.

How does one load the older version of the package?

Thanks