migrate windows 2000 domain into winodws 2003 domain controller

I would suggest you review the following links.  Every environment is different and as such, a generic detailed answer is not going to necessarily be appropriate for you.  Instead, read these links, upgrade at least once in a test environment, and you should be fine.

Here are some links that should get you going for upgrading a 2000 domain to 2003:

Common Mistakes When Upgrading a Windows 2000 Domain To a Windows 2003 Domain
http://support.microsoft.com/default.aspx?scid=kb;en-us;555040

How to upgrade Windows 2000 domain controllers to Windows Server 2003
http://support.microsoft.com/kb/325379

[If using R2 release of Windows 2003] Extending Your Active Directory Schema for New Features in Windows Server 2003 R2
http://www.microsoft.com/downloads/details.aspx?familyid=5B73CF03-84DD-480F-98F9-526EC09E9BA8&displaylang=en

Hotfixes to install before you run adprep /Forestprep on a Windows 2000 domain controller to prepare the Forest and domains for the addition of Windows Server 2003-based domain controllers
http://support.microsoft.com/?kbid=331161

Commodore.ca | Windows | How To Upgrade Windows 2000 Domain to Windows 2003 Server
Quote from the top of this article: "Several glossy Microsoft presenters have stated that all you need to do to complete a Windows 2003 Domain upgrade is run ADPREP and then upgrade away.  This may work for very small / simple environments but it is definitely not good advice for most companies.  After upgrading five servers in two unrelated domains and installing many fresh copies of 2003 I can say that I personally would not skip a single step in the process I have developed below."
http://www.commodore.ca/windows/windows_2003_upgrade.htm

Windows Server 2003 Upgrade Assistance Center
http://www.microsoft.com/windowsserver2003/upgrading/nt4/upgradeassistance/default.mspx




Here are some links that should help you in replacing existing domain controllers and/or transferring services and Active Directory functions to another/new system:

How can I transfer some or all of the FSMO Roles from one DC to another?
http://www.petri.co.il/transferring_fsmo_roles.htm

How To Create or Move a Global Catalog in Windows 2000
http://support.microsoft.com/?kbid=313994

How to move a DHCP database from a computer that is running Windows NT Server 4.0, Windows 2000, or Windows Server 2003 to a computer that is running Windows Server 2003
http://support.microsoft.com/?id=325473

How can I move a DHCP database from one server to another?
http://www.windowsitpro.com/Article/ArticleID/13473/13473.html

How can I move DNS from one Windows 2000 Server to another Windows 2000 Server?
(Two Related if going 2000 to 2003 - read both before moving)
http://www.jsifaq.com/subG/TIP3300/rh3357.htm
http://www.jsifaq.com/SUBN/tip6700/rh6731.htm



Exchange Considerations:
[If you run Exchange 2000] Windows Server 2003 adprep /forestprep Command Causes Mangled Attributes in Windows 2000 Forests That Contain Exchange 2000 Servers
http://support.microsoft.com/default.aspx?kbid=314649

Are you saying my links were of no relevance and help?

no its relavant... :)
Thanks for posting the comment.

So if it's relevant why not split the points.

Sorry I'm a bit in late, I'll post my reply asap!!!
Thanks a lot for your comments :)