I think all the distros are currently shipping with 2.4 as the kernel and you have to recompile manually if you want the 2.6 kernel. At some point all the distros will be shipping the 2.6 kernel. How do they decide when 2.6 is ready for prime time? Is there some official Linux board of directors who votes on things like this? Does Linus issue a proclamation declaring that the 2.6 kernel is ready? I'm just curious.

Well Linus has already declared that kernel 2.6.3 is ready - but that doesn't mean that distros have to ship it. I take it you are talking about ISO based distros - it's totally up to them what kernel version they ship with, and for a linux user it doesn't really matter cos you're perfectly welcome to pull down any version of the kernel at any time and compile it for yourself.
A lot of other distros don't work in this way - arch, crux, gentoo. You only have to 'install' once and then you just keep the system up to date yourself by compiling new packages and kernels - there's no waiting around for a new kernel to be supported.

Most distros will test the kernel out with their particular product before making it part of one of their latest releases, etc. There is no board of director's for Linux in general, Linux is maintained by one man, Linus and he has the say on the kernel which is what Linux is. All these other distros operate on their own, its their decision to include open source applications and updates, etc.

Heck, two years ago I saw a version that shipped both 2.4.2 and 2.2.4 (with the smp options included for multiple processors) so I can guess 2.4.xx was quite new at the time.

I guess there's still issue of "rigorously tested" ie. the difference between Einstein's theory and Newton's law of motion. The 2.6.xx kernels are still quite new, although so far they have been generally stable, they need to undergo more user experience, etc.

Although I can see them including it as an option soon. But they won't omit 2.4.xx yet....

stehyll include it when they want to, for me i have my entire lapop compiled again the linux 2.4.20 headers, and thats alos the kernel verosn i use, im not gonna change it, when i get a new computer i will include the lastest kernel tho, but im not gonna waste time just to put some enw kernel on when i got one that works fine, so itll take like a month il guess b4 tehy all have suport for it (its hard to kernels to work, must recompile soo amny times to hammer out a few bugs