Wire three way switch from existing circuit

[tonyenkiducx]

I have a light connected directly to a switch, with the power going into the light and running of to the switch. What I want to do is run a second switch from the existing circuit, and have it work as a three way. I have access to the light cabling itself, but the wiring on the existing switch is very inaccessible and I would greatly prefer to leave that switch intact, or just run an extra cable from it(I am equally happy to just run cable from the light).

How would I go about doing this?

 

[RF Lighting]

How many switches are you hoping to end up with? 2 or 3?
I can't quite work it out from your post.

Either way have a look at the last post by Spark123 on the last page of the FAQ, for full colour diagrams of both setups.

 

[tonyenkiducx]

Ahh, sorry, I should have looked there first. Hopefully that will do for what I want, as I seem to remember the light in the kitchen having one of those blocks on it. Fingers crossed.