I have yahoo email and everytime I get a new email per yahoo website, I don't get the email on my phone. Instead I get a bunch of emails from "no sender" "no subject" dated 12/31/69?!?! This just started happening today. I updated to iOS4 yesterday and didn't seem to have a problem?
If I go into mail settings to my account (do nothing) then go to my mail the 12/31/69 emails disappear?
I have the same problem with gmail. I have deleted all of the trash and spam in the gmail folders but I cant delete the 12/31/69 emails from the trash or inbox on my phone. They don't exist in my gmail folders.