There’s however an trusted option now that will let you view and print Project files in the browser itself without requiring MS Project. It’s called projec.to.How to Open Microsoft Project Files Online
To open a project file without installing Microsoft Project, just sign-up for a free plan at projec.to and upload your .mpp (or .mpt template) file.
The service will then render your project plan in a browser based Flash-viewer from where you can view the plan and also print it or even embed it in external web pages using Flash.
The service offers both free and paid plans but if you opt for the free option, any MS Project file (or Template) that you upload onto projec.to will be public by default.
You can also delete files immediate after viewing them online but if your projects plans contain something extremely confidential, it may be a good idea to go with one of the paid plans that start at $5/month and allow private viewing.