I just updated the Prepaid cell phone rates post here http://blog.nyphonejacks.com/2011/05/blog-post.html
It was about 5 months since I updated that list. In that time frame I have found that most of the pre-paid carriers rates remained pretty solid, with some changes - mostly in reduction of rates, or increased minutes for the same rate. What surprised me however was Verizon's rates seem to finally fall in line with most of the other prepaid carriers, which may lead me to pick up a Verizon phone when I go to replace my phone in the near future.
What I did not post was some of the smartphone rates - Verizon's blackberry prepaid plan is around $75, which is not too far off of what the other carriers are charging.