I am using iPC 10.5.6 final universal and have a completed install.
I then reboot and see darwin. I put in -f. And whatever I do it loops restart, nothing shows up on verbose.

Compaq Presario M2000
Inter Celeron M (SSE2)
(Successful install w/ 10.4.6 JAS)
Intel 82852/82855 GM/GME Graphics controller
Conextant AC-Link Audio
REALTEK RTL8139/810x Family Fast Ethernet
Broadcom 802.11b/g WLAN