I went to Scotland for 10 days with a friend about 12 years ago. We stayed at a Hilton (I think) on the Royal Mile in Edinburgh. We made all of our own arrangements....and without the Internet.

We relied on guide books and had no problems at all. However, if you would feel more comfortable, as golfgal mentioned, you might consider a
travel agent for your first International trip.
A couple of things I wanted to let you know about that happens every August (and only in August) in Edinburgh are the
Edinburgh Military Tattoo and
The Edinburgh Festival Fringe. The Tattoo is the largest gathering of bagpipes, drums, and other other talent and is a big International event. It is a very AMAZING show and was one of the highlights of our trip. I wanted to learn to play the bagpipe after this show.
The Fringe is a little hard to describe. I guess you can say it's a festival showcasing talent from all over - comedy, musicals, drama, concerts, etc. There are over 1500 different shows - some as big as broadway productions, most others in smaller venues that can hold 50 or less people. Tickets to the bigger productions (with well known stars) should probably be purchased in advance - all others you can just about get the day of the show. Quite interesting and fun!
From Edinburgh, we were able to do a day trip to St. Andrews - home of Golf. Quite interesting town! I'm glad we were able to do this. I would have liked to do more day trips from Edinburgh but my friend really wanted to soak up more of the shows in the Fringe.
In addition to these two events mentioned, Edinburgh has a lot to offer. I'm sure you'll have a good time - we sure did! I hope to go back someday and see some of the other towns.
Good luck in your planning!