is there a thread on how to install steel braided break lines want to get some for my 07 ninja 250

It's a direct swap you just have to know how to bleed brakes. I would definitely recommend them for the front though. I haven't installed mine for the rear so I wouldn't know the difference there.

It's easy, just try not to break anything. :p

To make your life a little easier I would buy one of these brake bleeders.

It makes working on your 4 wheel vehicle a hell of a lot easier as well.

http://www.harborfreight.com/catalogsearch/result?q=brake+bleeder

There are several DIY's in the main tech thread:

http://www.ninjette.org/forums/showthread.php?t=5586

They are all for the '08 model, but there should be very little difference with the pre-gen install.