I'm pretty new to Verizon's broadband service, and I'm really liking it so far.
I have been very careful to log in frequently and check my usage (I can't use VZAccess Manager because I'm behind a 3G router). The only problem has been that the usage information on Verizon's website is often a day or more behind.
A couple of days ago I found some free software that sits in my system tray and polls the router to give me cumulative real-time usage information. It remembers my billing cycle dates and knows when to reset itself. It also knows that if I exceed 5120 megabytes in a month it will cost 5 cents per megabyte.
The name of this software is Datacapper, and it can be found at download.com and other places. This is working out very well for me. The only downside is that it needs to be left running constantly in order to get accurate information. If you need something like this, take a look and let me know what you think. If you've got something better, please share.