Chain cleaning and lubrication questions

Greetings,
Just curious to know what I should use to clean my chain
with. Now that I've got a fair amount of time on the bike in the rough
stuff, the chain is starting to get 'gummed up'. I've always used kerosene
and a stiff brush to clean the chains on my motorbikes (being super careful
not to get it on any bearing areas etc) and it's always worked a treat. Is
there any reason why I shouldn't use kero to clean my mountain bike chain
too? What about cleaning the derailleurs and rear chain rings/derailleur
sprockets?

Which leads me to my next question......after cleaning, what's the best way
to go about lubing the stuff I've cleaned? I've got teflon based lube for
the chain, so that's not a problem. But what about the derailleurs and
sprockets?

The reason I ask is that my GF's rear derailleur is gummed up pretty bad.
We went for a ride on the weekend and swapped bikes for a while so she could
ride my VT3. When I tried to go back up the gears on the rear derailleur,
the assy was binding and not changing cleanly (or sometimes not at all).
The spring was having a hard time pushing the assy sideways enough for the
change because of the binding (it feels 'stiff' when I try to move it around
by hand). It's all indexed properly etc.....it's just very grubby! So,
it's time for a service. I'm quite prepared to do this myself (I certainly
have the tools and mechanical ability to do so), but I'd like to know where
and what sort of lube to use after I've cleaned it all.

I'd also like to know what sort of lube to use on my cables. I've got a
cable lubing thingo that I used to use on my motorbikes (rubber clamp thing
that seals over the cable and guide and allows lube to be forced down the
cable guide via an aerosol tube), but I'm not sure what sort of lube to use.
Does it matter? My rear brake cable is starting to feel stiff, so that's
why I'm asking.

Thanks!

MrBonk
www.mrbonk.com