Web-based project management tool Gantter has an interface that looks remarkably similar to Microsoft Project—and even lets you import and export your Project files.
Using the application is fairly simple—just start adding tasks and resources just like you would on the desktop version of Microsoft Project. Once you've finished, you can download the project as an XML file, which can then be imported back into Project. You can import projects, open saved files, and use the wide array of keyboard shortcuts all from a web-based interface that works anywhere and requires no account to use—making this worth a look for anybody dealing with project plans and TPS reports.
Gantter is free to use, available in your web browser. For more, check out free hosted project management with Clocking IT, or replace Microsoft Project with the open-source OpenProj. Thanks, Climbup!