Google today announced a major upgrade of Google Docs, stepping up its attack on Microsoft's core Office business of spreadsheets and word processing software.

"You shouldn’t have to give up any routine features when you switch to web-based applications, and we’re addressing many longstanding requests across Google Docs with this release that were not feasible with older browser technology," the company writes in a blog post today.

Among the changes are new spreadsheet and document features which allow easier placement of images as well as new formatting changes such as better numbering and bullets. Google also has improved its document uploader so imported documents are more easily formatted within the online program.

The speed of Google Docs also has improved, with the company noting that Web apps now feel "just as fluid as traditional software." That means easier more seamless collaboration, one of the hallmarks of Google Docs over the years.

Up to 50 editors now can work on one document at the same time with individual editors following changes as they occur. The company also added multi-user functionality to drawings, so multiple users can adjust charts, graphics and other diagrams.

VentureBeat noted last fall that Microsoft Office has about 500 million users worldwide, while Google Docs claims just 20 million. However, Google has made no secret of the fact that it wants to grab some of those traditional Office users -- and some are speculating that 2010 will be the year that it makes the big push.

Google has made some other moves in recent weeks, most notably purchasing San Francisco-based DocVerse last month.

Here's a quick overview of the new offerings from Google.