I've tried several different approaches to keeping journals and logs of my fishing over the years. I enjoy looking back at these logs and they are certainly informative for planning future trips.
So far, I have been unable to really stick with a single logging format for very long. I guess this is my own fault for simply not being devoted to keeping track of things.
The best free, online option I've found is http://www.mydailyfishinglog.com/ . This website is oriented slightly toward flyfishing, but the framework is flexible enough to use for any type of fishing logs. There is even the option to attach pictures to each individual log entry. The best part is that it is 100% free, all you have to do is create a username to login.
In the past I've also tried creating my own log forms in Excel. The advantage to doing this is that I can customize my log entry fields to precisely what I what, but the interface and ease of use is not quite the same as the online entry options.
I'm not much on paper and pencil, as I tend to lose (or misplace) notebooks, and they are always vulnerable to deterioration. As such, I haven't tried the old school method of writing down details from fishing trips, but perhaps I should.
Do you journal your fishing trips? What format to you use to record your information? Reply in the comments!