The Government approved the BBC's pound;150 million Digital Curriculum project last week, angering education publishers who fear the free website will cost them more than pound;400m in lost earnings.
But teaching unions have praised the scheme and the Government's Curriculum Online project, which was officially launched this month.
Eamonn O'Kane, general secretary of the National Association of Schoolmasters Union of Women Teachers, said: "They have the potential to be valuable resources, reduce workload and time spent planning and preparing."
The National Union of Teachers is working with the BBC on creating professional development materials for teachers which will appear on the completed version of Digital Curriculum.
John Bangs, NUT head of education, said: "Private publishers don't seem to understand the role of a public service broadcaster. The Digital Curriculum and Curriculum Online will be very important to teachers."
Digital Curriculum is unlikely to be available until the 2004 autumn term due to conditions imposed by Culture Secretary Tessa Jowell. These require the BBC to submit a five-year plan at least 15 months before it launches the service.
The delays give a head start to Curriculum Online which is intended to support commercial publishers and broadcasters who fear they will lose business because of the BBC's commitment to provide free online resources. Schools have more than pound;30m from the Government to spend on products registered at the website before August, and will then receive approximately pound;100m a year in e-learning credits.
At first, schools will receive the credits as cash but they will later be given as electronic money. A judicial review launched by the education publisher Research Machines against the BBC's Digital Curriculum service is expected to be heard later this month.