WiMAX may be used by Boost Mobile and Virgin Mobile for 4G connectivity
likely remain the same for Virgin Mobile and Boost Mobile. The former would offer unlimited data with the carrier throttling the data speed of those who exceed 2.5GB in data usage during a customer's billing cycle. The same plan would most likely apply to Boost Mobile customers as well.
None of this has been confirmed by Sprint, which is expected to start offering LTE service to its customers in June. Most likely Virgin Mobile and Boost Mobile will be the only part of Sprint's network to offer WiMAX connectivity although eventually Virgin and Boost could offer LTE service once prices for supporting smartphones come down in price. Remember, with no contract to lock in users, the two carriers cannot afford to offer a subsidy on phone purchases.
source: TechnoBuffalo via Electronista