Hey folks moments ago @Notcom the owner of Tiny Umbrella Tweetd that :
TinyUmbrella 4.21.06 released with 4.3b3 support as well as a nifty bugfix. (thanks for the info RobRedbeard)
Tiny Umbrella is now able to save your iOS4.3b3 SHSH, save them now in case you may need them in future like you needed the SHSH for iOS4.2b3. And remember Jailbreak Monte is a method and it is not a Exploit. Jailbreak Monte is the method which was used in the recent Redsn0w to do an Untethered Jailbreak on iOS4.2.1 using iOS4.2b3 SHSH. So save them now before it is too late.
You can download Tiny Umbrella from here and stay on a safe side.