Here's where I put on my 'company man' hat, jump up on a soapbox and scream out..."come and get it, come and get access to the Office Live Workspaces beta at OfficeLive.com!" 
Seriously though, it's official today: Microsoft Delivers Office Live Workspace Beta
An excerpt [emphasis mine...a personal pet peeve for years now]:
Customers have asked for an easy way to save their documents from Office to the web, so that they can get to their information or projects if they’re away from their PC. People also get frustrated with the confusing free-for-all that can result when multiple versions of documents circulate in e-mail attachments that then have to be manually pulled together by the original author. We’re hopeful that Office Live Workspace helps solve these challenges by providing a place online to keep a single version of a document that everyone can work on – so you’ll always know if you’re working on the latest draft.
Office Live Workspace also provides a seamless connection with Office on the desktop, which has been one of the most important customer requirements. For example, if I’m creating or editing a document in Word, I want to be able to save it to the web as if I’m saving to my own hard drive – no hunting around for URLs or saving and then uploading. We’ve seen that if people are working on a document and have to go to the browser to upload, many just can’t get over that hump. So we’ve learned you have to make it super easy for people to do things like get their documents from Office to the web, as well as to save work back to the web with one-click if they’re making edits.
I have played around with the internal beta [available only to employees] before this public one and it's pretty sweet. There are some obvious things missing, but if you use Word, Excel or Powerpoint and share documents [at work or home] then I think you'll be pretty happy with the experience. Not to mention, it beats the hell out of sending a 2MB word document as an attachment in email [personal pet peeve of mine]. 
Sign up at OfficeLive.com!
Check out the Workspace Team Blog. It's a little light on content, but hopefully that will change in the future. And here's an interesting article that has some good information in it.
By the way, Office Live Workspace is a different beast from Office Live Small Business.
~tod