The Samsung Galaxy Note II is the latest superphone from the Korean hardware maker. Announced in August, the device has already gone on sale in some markets around the world. Sales of the device from U.S. carriers begin this week.

T-Mobile USA is the first to offer the Note II. It is selling the phablet for a whopping $369.99. That's after a $50 mail-in rebate, which means the Note II is going to set you back $419.99 (plus tax!) at the register. Ouch. It can be ordered from T-Mobile's website starting today.

Unlike the other variants of the Note II, T-Mobile's does not support LTE 4G. Mobile data speeds are still quick on T-Mobile's HSPA+ network, however, which has a significant footprint.

Sprint is next to launch the Note II. It goes on sale October 25 via Sprint's website and select company-owned retail stores. Sprint's version of the Note II will cost $299.99 with a new two-year contract. Sprint is not requiring users to deal with the hassle of a mail-in rebate. It will set you back a full $120 less than T-Mobile at the cash register.

The Note II supports Sprint's LTE 4G network, but remember that Sprint's LTE network is limited to just 30 or so markets. Most people who purchase the Sprint Note II will experience only 3G data for quite some time.

[ Considering different form factors? Read Motorola's Wearable PC: More Than A Headset. ]

AT&T's variant of the Note II will be available for pre-order starting October 25, but it won't reach stores until November 9 (yeah, two weeks from now). Like Sprint, AT&T is charging $299.99 for the device with a new two-year contract. It appears that AT&T is avoiding the mail-in rebate hassle, as well.

The AT&T Note II supports LTE, and AT&T's LTE footprint has grown rapidly in the last few months. It is available in more than 60 markets, and should be available in 100 markets by the end of the year.

Verizon Wireless has yet to announce pricing or availability for the Note II. I would be surprised, however, if Verizon charges anything other than the same $299.99 prince point that AT&T and Sprint are asking.

What's the deal with the Note II? It improves upon the original in nearly every way. It has a larger screen, faster processor, better camera, improved S Pen (stylus) support and apps, and support for a broader range of LTE 4G networks. As long as you can stand the ginormity of the hardware (it is absolutely huge), the Note II is a good test case for the popularity of the "phablet" form factor.

Time to patch your security policy to address people bringing their own mobile devices to work. Also in the new Holes In BYOD issue of Dark Reading: Metasploit creator HD Moore has five practical security tips for business travelers. (Free registration required.)