MacNews.net.tc provides a "weekend roundup", but it is unclear what is speculation/old rumors/new rumors.
The site claims that PowerMac G5s will be updated in January up to 1.8GHz, 2.0GHz, and 2.2GHz. Previous claims from this site included 1.4GHz, 1.6GHz, and 1.8GHz PowerMacs at WWDC, which were incorrect.
PowerBooks are pegged at 1GHz and 1.33GHz speeds in a week, but previous claims from the same site have included 1.1GHz and 1.3GHz PowerBooks (July 19) as well as 1.25GHz and 1.33GHz PowerBooks (July 22).
As an aside: The top speed on the 7457 has been (presumably) confirmed to be 1.3GHz based on Motorola documents.
Also mentioned is the announcement of a "creative sound" iApp... a rumor that has also seen many previous incarnations.