Update 2: Looks like page was changed again to reflect the second add-a-phone being free. It was not there last night.
Update: Second line is no longer free on $100+ plans.
Today Sprint has launched new voice plans, you can check them out on sprintpcs.com. Most noteable change is that higher-minute plans now cost $20 a month for Add-A-Phone (again), and Vision is now only $5 per Add-A-Phone.
Also, Free & Clear America plans have been discontinued. Instead, there is now a $5 (per line) option that will allow you to have 50% of your airtime usage be off-network. This can be added by calling customer service on any plan. Unfortunately, it looks like this will be for corporate markets only, and maybe some affiliate markets.