I have been reading around here and can't find much. The java memory limit is set to max (1gig), I repaired the disk permissions. That actually helped, as in made the game last 20 minutes to crash instead of 2-5.
I might try to reinstall....
Any ideas?

oh, so error codes:

Before repair permission:
Process:         JavaApplicationStub [4099]
Path:            /Applications/Minecraft.app/Contents/MacOS/JavaApplicationStub
Identifier:      com.Mojang Specifications.Minecraft.Minecraft
Version:         Minecraft 1.0.0 (1.0.0)
Code Type:       X86 (Native)
Parent Process:  launchd [142]

Date/Time:       2010-10-04 15:16:26.865 -0700
OS Version:      Mac OS X 10.6.4 (10F569)
Report Version:  6

Interval Since Last Report:          1989689 sec
Crashes Since Last Report:           5
Per-App Interval Since Last Report:  7374 sec
Per-App Crashes Since Last Report:   5
Anonymous UUID:                      FBD3FF3F-06CC-44FF-8823-A5EF5AA0E1C5

Exception Type:  EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000000000000
Crashed Thread:  20  Java: Minecraft main thread

error 2 after permissions repair
Process:         JavaApplicationStub [4163]
Path:            /Applications/Minecraft.app/Contents/MacOS/JavaApplicationStub
Identifier:      com.Mojang Specifications.Minecraft.Minecraft
Version:         Minecraft 1.0.0 (1.0.0)
Code Type:       X86 (Native)
Parent Process:  launchd [142]

Date/Time:       2010-10-04 15:58:34.014 -0700
OS Version:      Mac OS X 10.6.4 (10F569)
Report Version:  6

Interval Since Last Report:          1992217 sec
Crashes Since Last Report:           6
Per-App Interval Since Last Report:  9121 sec
Per-App Crashes Since Last Report:   6
Anonymous UUID:                      FBD3FF3F-06CC-44FF-8823-A5EF5AA0E1C5

Exception Type:  EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000000000000
Crashed Thread:  20  Java: Minecraft main thread