A few years ago I got really frustrated trying to maintain a schedule for my current development assignment. I personally think that having a schedule, or work plan, is a very good thing. But it was too painful to maintain one, so I started writing a tool that would help. The result, now in its third major revision, is the esmithy.net Work Plan Editor.
Joel Spolsky, in his book Joel on Software (a good read and with a really long subtitle) counts having a schedule as one of the virtues of a good software development organization. He also devotes a chapter to explaining why it isn't so hard to do. I generally agree with what he has to say except for point number one: Use Microsoft Excel. His argument is basically that Microsoft Project is too complicated, with which I agree emphatically. He also says later that developers tend to not use Excel for anything other than schedules, so... um... it makes sense somehow. OK, Joel helped develop Excel, so maybe he doesn't loathe it like I do.
One of the real weaknesses of Excel for keeping a schedule is that it is hard to get a mapping from task estimates to actual dates on a calendar, which is what my managers tend to be interested in. One of the guys I used to work with spent hours and hours to put some script behind a spreadsheet to do that mapping, and it still ended up being pretty flakey. It's not horrible to do the mapping by hand once or twice, but in my experience, schedules are highly dynamic and it gets old really fast to recalculate everything when a few tasks get added, removed or moved around.
In writing Work Plan Editor, I've tried to stick with the principle of Joel's point about Excel: Keep it simple. It has the features that you'd expect in an application (exporting, printing, recent file list and such) but is still pretty slim. It has also been a great opportunity for me to learn about .NET, C# and Windows Forms. I've also learned a little about ClickOnce deployment, which is how the application is distributed from the software section of my site.
Feel free to take it for a spin to see if it can be helpful for you.