Having launched to most of the world last June , I'm a bit late to the party but was interested in taking a peek at it's capabilities. It seems to be advertised everywhere now.
Signing up to the trial and checking it out is well worth a few minutes of your time - even just to get an idea of how 'rich in functionality' future web apps are going to be.
In particular I was interested in how excel works 'in the cloud'.
Excel in Office 365 falls under their Office Web Apps banner , browser-based scaled down versions of of Excel,
Word, OneNote and PowerPoint
There is slight lag , you see the old 'progress indicator ' every so often but overall it's a comfortable experience.
You can download your workbook locally ,take a snapshot with only the values and even email it from you 'outlook in the cloud'. Autosave is a nice feature too.
Worth a look, installing things on your desktop is so 1990.