ST. PETERSBURG, Fla. - PSCU Financial Services is extending its partnership with payments specialist CheckFree, continuing a relationship established in 2000 and offering additional CheckFree services to PSCU's client end-users. The big CUSO will continue offering the widely used CheckFree billing and bill pay platform, branded the PayLynx system, and now will add the i-Series hosted software solution that allows credit unions to send credit card statements electronically to online bill pay members. That service will be branded StatementSource by PSCU and will operate on a platform that can be used to help credit unions deliver other statements electronically in the near future, says David Serlo, president of PSCU Financial Services, which services more than 500 credit unions nationwide. Atlanta-based CheckFree, meanwhile, was a pioneer in bill pay, launching an integrated service in 1997, and now delivers about 22.5 million electronic bills each quarter.