The leather on a Brooks is pretty darn thick and tough, so if there's an actual rip in it, you might be out of luck. (the leather IS the saddle, that's all there is, a big hunk of leather suspended over a frame) If it's a gouge, you might be ok.

See if your LBS can get you a tin of Brooks Proofhide. Warm it in your hands and rub it into the leather. Might take a few applications until the leather isn't thirsty anymore.

I used to restore leather bound books, and you'd be amazed at how dry and crumbly leather perked up with just some dubbin!

For extra help (especially if there is a real rip or separation or something else awry) you could call Bill at Wallingford Bicycle Parts. www.wallbike.com He's a nice guy and really knows Brooks.