Verizon is no longer paying commissions on new or renewal POTS as of 9/1/10. This includes Mass-Market and Mid-Tier Customers. Other changes include: discontinuing commissions for Renewals for any Mass-Market customers (20 employees or less) and a decrease in commissions of 57% for Mid-Tier Customers.
Resellers of VZ services like Granite, TNCI, MetTel, and Ernest will continue to sell and compensate POTS lines.
I have to say though, if POTS is your bread-and-butter, you are looking at the end of that bread line.