After reinstalling my developement environment so it would run on a Windows 2008 server in 64 bit to accomodate the requirements for a future update to Sharepoint 2010, I found my self searching the web for guides on installing Sharepoint on a 2008 box, I've done it before but naturally I have forgot all about how to do it, so here's a guide to how you should go about that.
First you need to download the two updates for WSS and MOSS respectively,
http://www.microsoft.com/downloads/details.aspx?FamilyId=79BADA82-C13F-44C1-BDC1-D0447337051B&displaylang=en
http://www.microsoft.com/downloads/details.aspx?familyid=B7816D90-5FC6-4347-89B0-A80DEB27A082&displaylang=en
just save them to any location you prefer, it's not important.
You need to copy all the sharepoint installation files to you harddrive.
open a command prompt and navigate to the folder where the updates are saved and type the following command:
Select the location of you Sharepoint installation files
It's important that you select the Updates folder for the extracted files.
Press OK, a EULA will be shown
Accept the terms and press Continue
Repeat the steps for MOSS SP 2
Select the same folder as before
Accept the license terms
Verify that all files has been extracted to the Update folder, and you are ready to install Sharepoint
SP 2 is a cumulative update which means that it contains all previously released updates, more info an be found at these KB articles http://support.microsoft.com/kb/953338 http://support.microsoft.com/kb/953334
Enjoy!