Your first port of call of course is going to be the free software and without exception there are some amazing titles, such as PHD Guiding (Press Here Dummy) and Stellarium. But amidst all of this the black art again takes over, as guiding is well practiced, but by no means standard, most peoples guide set-ups are particular to them and how they wish to guide.
This information is completely confusing for a beginner and seems altogether like a huge mountain to climb. Enter Steve Richards. Steve is an astronomer like you and I, he doesn't have the biggest and best kit, he has "normal" equipment and a sensible head, I looked over his site which can be found here, and slowly I began to fell a whole lot better about learning to guide.
The first thing Steve does is let you know that you are not alone, and that everyone who has learnt astrophotography and guiding had to start somewhere, Steve also has a book which after looking at his site I bought and it has become my bible, the book can also be bought from Steve's site (I am no relation by the way just very very enthusiastic)
From reading Steve's work I was better able to make an informed start at guiding and have even fabricated a mount to take my guide scope on to the top of my 6" Celestron SCT, the biggest thing that Steve's writings have helped me with is patience, patience to take my time and get the set up right from the start.
I have chose the excellent Equinox 6 software coupled with Astroplanner and will guide with Equinox 6. I also have a GPSUB for direct connection of the ST-4 port on the mount for smooth guiding, for an explanation on GPSUB and ST-4 then please look at the excellent tutorials on the Equinox 6 website under the "Autoguiding" tutorial.
I will initially be imaging with a Phillips Toucam Pro webcam using Keiths Astoimager, and also a Nikon D40 DSLR at prime focus.
I am able to talk like this, and be confident in my writing thanks to thorough research and great support from good friends on Twitter, you can find me on there just look for @craiggold.
Now if the cloud EVER clears I will be posting my first images with my new setup.
I wish you all the luck in the world if you are just thinking about guiding and astrophotography, but I promise you, it's really not as bad as you first think, just do your homework and talk to as many people who guide and photograph as you can, as they will have made all those mistakes that you want to avoid already.
Good luck and dark skies to you all.