There are a number of project management tools you can use. None of which is a substitute for solid planning. Tools make the planning and project management easier, they don't necessarily make it more accurate. Keep that in mind as you work on your next project. I've never seen a tool that's a silver bullet. I have used tools that have made my ability to manage projects more difficult, but that's another post.
I've used post-it notes to develop plans. They are actually a pretty good tool. You write your tasks on each of the notes. You can then put them on a white board, and draw the successor and predecessor lines between each. You can erase, and move them very easily. It's actually a pretty good option to develop a plan when a team is brain-storming. Once you have them set, you can transfer them to paper, or a spreadsheet... or some other tool.
As far as tools, I've used basic excel sheets - you can setup columns as buckets of time. You can also use Google Docs. They have some gadgets to help with creating the gant chart.
I have also used pure project management tools. Timeline was an older tool, and was actually pretty good at creating gant and pert charts. I really like using Microsoft Project, I like the different views, and drag-n-drop flexibility. I have used Project.Net -- it was not one of my favorite tools. There were some issues with blogging and summarizing hours reported against project tasks. Creating and managing plans was also difficult.
We will soon be journeying into utilizing Computer Associates' Clarity Project Management suite. This is a high-end tool that should be very helpful. It has some interesting features like skills inventories, time card reporting of indirect time, and others. We evaluated this a couple of years ago, and it appeared to be a very respectable tool.
In summary, it's not the tool that manages projects. It's your job to manage projects, so pick a tool that you can learn to use... and use it wisely. It will help you plan and track your projects... it can't tell you how to plan or manage... that's something you need to learn.
