Installing the beta is very tiring. If you wanna attempt you got to make sure you have other meaningful things to do while your PC is crunching Microsoft's latest beta.
The download is 440Mb. If you still wanna get the very latest one there is a B2TR version, which stands for [tag]beta[/tag] 2 Technical Refresh, again another 494Mb.
By the way the most important note is that if you are using [tag]Office 2007[/tag] at work and will be getting resources from your exchange server the [tag]Outlook[/tag] may not work at all. I had to go back to Outlook 2003 due to compatibility issues with older version of exchange server.