The devs have plans to support 64 bit, but it is just one thing on their extensive 'to do' list. There is no clear timeframe for 64 bit appliances to be availble.
Assuming that your interest in 64 bit is because you want to use lots of RAM; the next TKL release will be based on Ubuntu Lucid so should AFAIK support up to 64GB RAM (via PAE). I have not tested that but you could test TKL-Core-Lucid beta if you want. I'm sure others would be keen to hear how you go.
 Have just been having a read over on the Ubuntu forums and apparently vanilla Lucid (the base of the upcoming TKL release) installs PAE by default when more than 3GB RAM installed. I'm not sure if this behaviour will also happen with TKL but should be easy to enable even if its not. Have a read here if you're intersted.
Also if you have some other reason for wanting 64 bit please share.
That makes perfect sense. Oh well, perhaps someone else will find the info that I've posted helpful.
Anyhow, I hope the people who come across your posts are taking notes. Your writing is not only informative, but also friendly, accessible and always humble to a fault! The Intertubes would be lucky to have more people like you setting the standard for online discourse. Have you seen what passes for commentary elsewhere? The comments on some of the world's largest sites (e.g., YouTube) make me want to gouge my eyes out and pray for humanity.
More information about formatting options