Any developers with access to the beta have idea whether my 2008 macbook pro is still supported on Mavericks?
Hopefully nothing changes by the time that Mavericks comes around, but I think those of us with the 8600M GT pros have had a pretty good run (bad cards aside). My computer came with 10.5 Leopard and it looks like it'll be able to run 10.9 as well... that's 5 OS'es. I had an iMac that came with 10.4 and topped out at 10.6... only two OS upgrades.
I was about to feed mine to the dinosaurs, but I gave it a 256GB SSD 6 months ago...with the intention of prolonging its suffering another 8-12 months. Just enough to get me to Haswell rMBP.