SharePoint 2007 Installation on Windows Server 2008

1. You must enable the IIS7 Feature Role on Windows Server 2008 with .NET 3.0
-From Control Panel, Programs and Features, Select 'Turn Windows Features On or Off'
-Next, Under 'Server Manager, Features' Select '.NET Framework 3.0 Features'. When askedto install the IIS7 role, select yes.
-Under IIS7 'Security', be sure to select the authenticationyou want, i.e. Basic, NTLM, Kerberos, etc.
-Next, you must slipstreamWindows SharePoint Server 3.0 SP1 AND SharePoint Server 2007 SP1 into your SharePoint Server 2007 installation directory.

2. I used Winrar to extract the files from my SharePoint Server 2007 ISO, but you can alsocopy them into a directory directly from the DVD. Create a directory, we'll use c:\Slipped for our installation point. Copy the entire DVD contents to c:\Slipped

3. Next, you must download and extract both Windows SharePoint Services SP1 and SharePoint Server 2007 SP1you can get them here
http://blogs.msdn.com/sharepoint/archive/2007/12/11/announcing-the-release-of-wss-3-0-sp1-and-office-sharepoint-server-2007-sp1.aspx

-Create a directory to host the WSS 3.0 files after extraction. We will use c:\wsssp1
-create a directory to host the SharePoint Server 2007 files after extraction. We will use c:\mosssp1
-we will assume we have downloaded both service packs to c:\

Extract the WSS 3.0 service pack files by executing 'c:\wssv3sp1-kb936988-x86-fullfile-en-us.exe /extract:c:\wsssp1' Agree to the license terms, and the service pack will unpack.

Extract the SharePoint Server 2007 service pack by executing 'C:\officeserver2007sp1-kb936984-x86-fullfile-en-us.exe /extract:c:\mosssp1' Agree to the license terms, and the service pack will unpack.

4. Copy the service pack files from the above directories into the installation updates directory.
5. Last, run the setup from the x86 directory, and it should install!

Note:-Microsoft has now released a slipstreamed SharePoint Server 2007 SP1 image here

Additional Resources:
MOSS and WSS SP1 files are located here. You will need both service packs for the slipstream installation. Note: the links have both the 32 and 64 bit versions.
WSS SP1: Windows SharePoint Services 3.0 Service Pack 1 (SP1)
MOSS SP1: The 2007 Microsoft Office Servers Service Pack 1 (SP1)

I hope the above information helps you to install sharepoint on windows server 2008 successfully.
All The Best !