Lately I’ve started making use of the Stickies app that is included in the Mac OS. I often jot down notes and URLs at work on small pieces of paper. If I don’t get a chance to follow through on some of my items, I type them in a sticky note. I now keep several notes running on things to do, bills due, hate list ideas, blog ideas, etc.. I keep another note open just to cut and paste URLs and stuff.
There are many ways to customize your notes. I found a good page that lists several ways to spruce up your Stickies here.