Oh well... BigBro is watching ya: Just out of the fun of it... What it'd be to have warm hands during those winter rides?!

Here's what a couple of hours' worth research on the net gave me:

First of all, I had this catalog in print from the nice guys at Aerostich mailed to me. It was there that I first came up with the idea of warm hands... A nice idea indeed!

Just remembering my last return trip on the KTM on the motorway a few weeks ago, in rain and cold... well... it would make sense to have this nice kit of thing to both my bikes...
Some Manufacturers and Retailers of heated grips:
Hot Grips are among the most popular grips in the internet, at least! They cost $110 and can be applied to all airhead, oilhead, K-models and F-models.

However, Aerostich have them advertised at $87. Pick your choice!!!!
Custom Heat Inc make heated grips for every bike manufactured.
(See how they are installed on a BMW R1100RT, below).
Heeters.com offer various sets for motorcycle and ATV evaluations. The ones in their site are of the 1 in. variety, and cost about $119.
Bits-a-bikes from UK have these Griptronics heated grips which are open ended (for bar-end-weighted bikes), draw 1.5A, are 22mm in diameter and cost 39.99 GBP.
Newtronic Systems LTD from the UK have their own heated grips system.
they will fit most bikes with 22 or 25mm handlebars, are self regulating and consume as little as a stoplight bulb. Prices range from 41 to 53 GBP.
dexdirect.com sells the Motrax grips. Same spec (and same price and pic!) as the griptronics above.
Dual Star have these heating elements, rugged, simple and effective, which stick under your grips. the price is cheap too at $29.95 but they ship only to the USA and Canada, currently. If otherwise, you have to get into some sort of paper/faxing "troubles".
Warmnsafe offer the Heat-Troller in various configurations, from $49.95 to 119.95
This device can be made to work with almost every kind of heated grips, and provides a good temp ranging.
Hein-Gericke offer two sets of heated grips. The basic goes for 19.95 GBP and the Daytona for 42.95 GBP.
Mind you this is the English speaking site of HG. If you wish for the German site it's at www.hein-gericke.de.
In the English-speaking site, in the Menu go to techincal/accessories/optical tuning.
This is the original BMW kit for the R-series oilheads. It costs way too much, at around 180-220 Euros/$, so it makes sense why everyone is trying the cheaper aftermarket things...

Installation methods on various bikes (All VERY useful reading).

Hot Grips for a Kawasaki Concours

Hot Grips on a Suzuki SV650S

Hot Grips on another Suzuki SV650S

Hot Grips on yet another Suzuki SV650S

Original BMW heated grips kit installed on a BMW R1100RT.

CustomHeat grips installed on a BMW R1100RT

The Hot Grips installation FAQ courtesy of the www.f650.com

Dual Star fitted on a Yamaha FJR1300

Dual Star/Kimpex heated grips on a Yamaha FJR1300

Installing Hein-Gericke heated grips on a Honda ST1100

Make your own heated grips very cheaply! Joerg has the answer!

How to make your own Electronic Heat Controller, by Philip Herzog
(and in case you cannot read German, like me, try this link for a comprehensive translation into English. There's more interesting stuff in this site).

And a few thoughts of my own...
1: All detailing in this page, like specs and prices was taken from the original sites, with good faith! I've yet to try any of these products!
2: All links will open a new window, so don't be surprised if your popup killers start buzzing! I'm using a good ol' text editor to make these pages, so there's not really any hidden treasures underneath, except for my silly old counter. And that's for the fun of it, really!