This post hasn't been updated in over 2 years.
When Apple announced that they were shutting dow MobileMe at the end of June 2012, they offer MobileMe customers a deal to ease their switch to iCloud. The company offered 20GB to all existing MobileMe users until June 30, 2012; however, Apple’s website suggest a change in the deadline. It now reads September 30, 2012.
Apple’s FAQ page was also update, so the prolonged time is valid. When the free trial ends, customers who wish to keep their 20GB of storage can pay or accept the downgrade to 5GB.