I'm not sure how technically savvy her books are but have you read Connie Willis?

Time's Eye by Arthur C. Clarke, published a few years ago.

I agree with the Connie Willis comment. I loved "Doomsday Book" which is about an Oxford student who travels back in time to study Medieval England and due to a complicated mishap winds up there during the Black Plague.

She also has a sort of sequel (with different characters) called "Blackout" but I refuse to read it until Part II comes out-in October, 2010-I think as the book ends on a cliff-hanger.

Some readers feel as if the book To Say Nothing of the Dog is part of the Blackout and it's companion book. I read both, and I was glad I read To Say Nothing of the Dog first, I think I would have too many questions otherwise.

I don't know how technically savvy he is, but have you tried Jack Finney?
Time and Again
From Time to Time

I was also surprised to discover that he wrote Invasion of the Body Snatchers.

The Time Traveler's Wife is a wonderful book but not sure if it's quite what you want. It's more romance than sci fi, but she explains the time travelling thing well and it's very coherent and consistent in that regard.

Try Michael Crichton's Timeline. I fell in love with it after my physic teacher suggested it. Chuck Palahniuk's Rant is another mind bending time travel themed book but it isn't as technical as Timeline.