Here's a cool piece of software - AdwordsReporter.
I've just started using it, as seeing trends for our Adwords advertising is pretty hard to do in the Google Adwords website. With AdwordsReporter you have to create an Adwords report and then import the .xml file into the program. From here you automatically get a graph of the date range you specify, and it's easy to change which data values it graphs. It's great to be able to see what effect changes you make has on the clicks, impressions and so-on. For example, we increased our Adwords budget in mid January and this lets us see very easily what effect this has on impressions, clicks, daily spend, position, etc.