It was a long time, since I needed to install windows XP on a Mac with Boot Camp, a lot changed ...

My first bootcamp was on a macbook core duo, then on an Imac 24 white, still working and no issue during the install.

But now I need to install a recent XP on an Imac 20 alu.

Don't expect to install windows XP SP3 directly, it does not work at all, after many tries I found some informations that says: Install bootcamp 2.1 (Leopard is shipped with 2.0), then install sp3.
In fact BootCamp 2.1 is a windows only executable and it's just fresh windows drivers that permits SP3 installation, don't know why Apple call it "Bootcamp 2.1", people like me will expect a Mac update ...

So first install Windows XP SP2, then BootCamp 2.1 for windows XP (inside your windows), then install Service Pack 3 from Microsoft.

For some stupid reasons I've also run into a strange issue, Disk error after windows XP SP2 installation, seems you need to delete the Bootcamp partition created by the mac and create it again inside the windows installer, read this apple doc.

Also think to remove all externals drives, or it will not boot correctly.

EDIT: Not finished, hal.dll problem and Disk error: If you fornat in NTFS you will suffer the hal.dll issue, if you fornat FAT32 boot disk issue.
Finally all my problems with SP2 had the same origin: this problem appears only on 10.5 with an "answer file" windows XP installation cd, an installer that answers all the questions for you. It's new in Leopard (cause the same cd worked with Tiger).
Confirmed another CD that asks all questions work better, don't know if it's a good way to find a good cd, but the one that worked ask to type F for format, the other don't.

One afternoon for this stupid windows installation.