Check out the sticky in the CRICKET forum.I'm not sure if it changed recently,but,the sticky was posted early 12/2011.
The TOS regarding tethering may pre-date the sticky,I'm not sure.
CRICKET has 3 different data plans for their mobile broadband,but,I don't believe they have an actual tethering plan for their phones.
Even if tethering was a part of their "unlimited" smartphone plan,you'd just end up getting throttled that much sooner into your billing cycle.
As we all know,it doesn't take long to burn through 1GB of 3G data.