Beta 2 installs on PPC systems, but errors out when trying to configure the boot loader. Here's the text from the alert window:

"An error occurred during boot load installation. Retry boot loader configuration? yes no" 

If you say yes, it gyrates around a bit and then displays the same alert. We have been able to get around this by booting from a SLES9 install on another disk (we copied the kernel and initrd over and edited yaboot.conf on the old OS). FYI, here's the disk partition table from the new OS:

Disk /dev/sdb: 36.4 GB, 36401479680 bytes
255 heads, 63 sectors/track, 4425 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1         157     1261071    6  FAT16
/dev/sdb2             158        4425    34282710    f  W95 Ext'd (LBA)
/dev/sdb5             158        2966    22563261   83  Linux
/dev/sdb6            2967        4272    10490413+  83  Linux

Obviously, there's no PReP Boot partition. We have had this problem on two different systems - one was a 550a (which is pre-release hw) and on a 520 (which has been out for ~2 years).

Note - I work for IBM. I'm sure there are "offical" channels this should have gone through, but I don't know what they are. It's a *big* company. ;)