What's the best way to keep a checkbook?

I always forget to keep track of what’s happening in my checking account. This had led to many overdraft fees in the past. I’ve gotten better now, but I still don’t keep track of the amount in my checking account every time it changes.

I know the good ol’ fashion checkbook is usually what people do, but I just don’t find that easy to use and it requires actual ‘hand-writing’ which nowadays with computers is becoming practically obsolete.

So, what other ways are there to keep a ‘checkbook’ per say? Most likely using some application on my computer. My bank does have an on-line service, but some things like buying gas don’t go in right away. So I’d like something to possibly remind me to record purchases for the day that’s easily accessible.

I have a laptop and an iPod Touch. If there’s an app out there for the touch, that would be perfect. Any ideas? What do you use to keep track of spending, if at all?