here in the USA offers a "Barrel Kit" in a variety of sizes.
I've been meaning to give this a try but have yet to get around to
ordering. As someone who owns two JD barrels, the Wasmund's
pricing is quite reasonable.
[edit to add - I have e-mailed Wasmund's twice (April & June 2009)
asking for specific details on this program but received no reply.
That may explain why I never got around to ordering...]
By the way, I first learned of the Wasmund's program on John Hansell's blog
MJL is correct about the selling of spirits in the barrel. Wasmund's
sells you the empty charred barrel with the bottled spirits which
you put in the barrel and age as you like.
On a related note, the Bourbon Dork recently started a "re-barrel
with some Very Old Barton BIB. Click "newer posts" at
lower left of the post for the progress.
edit: I e-mailed again and did receive a reply from Rick
Wasmund regarding the barrel program. I hope to set
something up soon!