Of note is the first message and the URL to get a revised AppleSCCSerial.kext. I am not savvy enough to fully understand the issue here, but it's something to do with a bug in the Mach kernel memory allocation.
Anyway, I have been using the revised kernel extension for a couple of days and the improvement has been dramatic. Check it out!
[Editor's note: I believe this fix is due to be rolled out with the next system update, based on an email exchange I saw on an OS X mailing list ... but if you'd like it now, it's available. I can't vouch for its effectiveness.]

