Create and share your projects online and access them from anywhere with Google Drive. Requires free account.
Create documents, spreadsheets, presentations and drawings or upload existing files. You can easily do all the basics, including making bulleted lists, sorting by columns, adding tables, images, comments, formulas, changing fonts and more.
Google Drive accepts most popular file formats, including DOC, XLS, ODT, ODS, RTF, CSV, PPT, etc.
Once saved, anywhere you can access Google, you can access your documents. Your documents will be private by default, they cannot be retrieved through searches. However, you do have the option of sharing your documents or publishing them to the Web.
To collaborate, enter the email addresses of the people with whom you want to share a given file and send them an invitation. Anyone you've invited to either edit or view your document or spreadsheet can access it as soon as they sign in.
Multiple people can view and make changes at the same time. There's an on-screen chat window for spreadsheets, and document revisions that show you exactly who changed what, and when.