As title says the expected 4.0.2 update, to fix the exploit used by jailbreakme.com, might be released today according to dev team member CPICH. Remember to save your SHSH blobs using TinyUmbrella if you haven't already. Since 4.1 will be released in a month or so I don't see the dev team wasting an exploit on 4.0.2, so anybody who accidently upgrades without their SHSH blobs will be unable to jailbreak till then.