Do a search here or in Google for ppc bid management software. If you choose to purchase one, verify that they are an approved third party tool for that PPC engine.
I've done some research in this area and have been able to effectively trim out the fat in my clients PPC campaigns. I'll use Overture as an example...
Overture allows 24 automatic bid updates in any given 24 hour period. Since my clients are US based and cover from East to West, I have different time zones to factor into the bidding equation.
Everything I do in PPC is automated. I'll never, ever, ever try to manage a PPC campaign manually, ever! Did I forget to mention that I would never manage a PPC campaign manually? ;)
To make the most of the automation, I've narrowed down my clients prime selling hours based on statistical data. I then set all my parameters in the bid management program for each keyword phrase.
For my West Coast clients who are regionally specific, I typically configure everything based on the time frame of 0600 to 1900 PST (Pacific Standard Time). During that time frame, I make the most of my 24 automated bid updates. I usually spread 18-20 through the prime selling hours and then the balance of them during non selling hours.
For my East Coast clients, I adjust the time frames to coincide with their time zone.
I also do quite a bit of Gap Surfing and have pretty much mastered it! I can tell which of my clients competitors are using bid management software and those who are not.
Gap Surfing takes advantage of gaps in the bids. It's a fairly complex issue but once you grasp the concept, you can really focus in on your ROI and manage bids more effectively.
Anyone who is doing PPC should be using a Bid Management Program. If they are not, then they are not managing the campaign correctly and missing out on a wealth of automated opportunities. ;)