You’re looking quite ahead into the future if you are asking that question. There will be many releases of different bits of software, mainly operating systems but there will be quite a few that are directed at certain types of customer.

 Windows Vista Beta 1 – beta version of the next client operating system from Microsoft
Released to testers only 3rd August 2005.

 Windows Server “Longhorn” Beta 1 – beta version of the next server operating system
Released to testers only 3rd August 2005.

 Windows Server 2003 R2 – update from Windows Server 2003 and has many new features
Released 7th December 2005.

 Windows Small Business Server 2003 R2 – update from Small Business Server 2003 for simple management
Released 1st half of 2006.

 Windows Server “Longhorn” Beta 2 – beta version updated from Beta 1
Released Q2-Q3 of 2006.

 Windows Vista – the released-to-manufacturers edition of the next client operating system from Microsoft
Released 2nd half of 2006.

 Windows Server “Longhorn” Beta 3 – beta version updated from Beta 2
Released Q1-Q2 of 2006.

 Windows Server “Longhorn” – won’t be called Longhorn, but it’ll be released none the less
Released 1st half of 2007.

 Windows Small Business Server “Longhorn” – the next generation of simple server management
Released Q3-Q4 of 2007.

 2008/9 onwards -
Service Pack for Windows Vista
Service Pack for Windows Server “Longhorn”
Windows “Vienna” (next client on)
Beta 1 of Windows Server “Blackcomb/Vienna” (next server on)