Mozilla is chemspilling 8.0.1 this week, probably today or tomorrow, to cover bug 699134 and bug 700835. Bug 699134 affects only Windows, and bug 700835 only affects the most current release of Java on 10.6 and 10.7, so neither is relevant to us.
As for the 9 beta, I am waiting for a couple issues to shake out. When Mozilla marks beta 2, then we will pull and port. On deck are some more AltiVec ports from Tobias and some infrastructure changes. The methodjit port continues and can compile simple expressions, but YARR behaves badly or crashes. Ben and I are investigating this in more detail, and the possibility of forcing a compiler update to gcc 4.2 is being considered if it turns out 4.0.1 miscompiles YARR on PPC as well. Methodjit is still slated optimistically for the Fx10 timeframe; it won't be in 10.4Fx 9.
Just for fun, because I am a Forth nerd, here is a beautiful implementation of Jonesforth written in pure PowerPC assembly language. It still runs perfectly on 10.4.
Stay tuned for the 9 beta!