Now my favourite counter to 1.e4 has been the scandanavian (1.e4 d5 2.pxp nf6 3.nc3 etc.) for a long time. But I've decided that I want to learn to play the scillian for a bit of variation. Can anyone teach me the main lines of the scillian dragon?

Looking at the diagram I'd say you've got the basic idea :P the dragon is pretty complex, and its name is by far the coolest :)

Best thing to do is study the dragon with the help of a book or some chessbase training cd I guess. Perhaps it's smart not to go for the sharpest lines right from the beginning, but study those a little first. 

Here some general tips for playing the Yugoslav-attack (when white goes f3, 0-0-0, h4 etc.) 

Never play e5 as long as you have a bishop on g7 (your dragon)

don't be afraid of pawn rushes towards your own king, your dragon will cover all :)

watch out for Bxf6, Nd5  (double attack on your Qc7 and Bf6 destroying your pawn structure) or e5-dxe5 g5-Nsomewhere Qxd7 trickery

Always remember that if you catch some pawns on g4/f3, they can become an attacking-force. 

Try not to sacrifice rooks on c3 as long as white hasn't sacrificed a pawn on the kingside, as you won't have enough compensation in the endgame (most of the time that is) 

won any nice games with it by now?