I just installed the update today on my Acclaim. I was excited to see the mobile hot spot show up on the upgrade notes. I went to turn it on and seen the disclaimer pop up. I called US Cellulars customer care line and asked if I will be charged to use it as I do not have the tethering plan. She put me on hold to check the release notes ande came back and told me there is no charge for it. She did remind me that there is a 5 gig cap, and said you run the risk of going over with some usage.
I think this is competition working in our favor. With Verizon getting the Iphone, and mobile hotspot is an advertised feature and US Cellular needs this to compete. The way I look at it, I am paying for 5 gig of internet, who cares if I used my phone or a netbook through my phone.