Disclosed is an integrated health plan computer system that enables on-line billing related transactions. The integrated health plan computer system may include a server to couple the integrated health plan computer system to a billing entity user through a network. A billing module operable with the integrated health plan computer system and the server is utilized to enable on-line billing related transactions for the billing entity user through the network. The billing module includes an invoice presentment module to perform invoice presentment transactions for the billing entity user and to display results of the invoice presentment transaction to the billing entity user. The billing entity user may be a group administrator, a broker, or an individual.