http://www.eyetotheuniverse.com/Polar%20…
Autoguiding is using a separate telescope that is bolted to the main scope and sends drive correction signals to the main scope, keeping it on track. The better your polar alignment is, the less work the guider has to do.
http://uncle-rods.blogspot.com/2010/09/u…
http://www.widescreen-centre.co.uk/Catal… <-UK vendor
One of the most widely used autoguiders (although not the best), is this combination -
http://www.telescope.com/Astrophotograph…
What you might want to consider is getting the Celestron for now, get used to how an EQ mount and polar alignment works and start saving up for the camera end of the process (say in a year). You'll have way less problems to deal with, since the telescope operation will become second nature to you and then you can focus on all the stuff that can go wrong with the camera equipment.