Broadcast company Crown Castle, which owns a stake in Freeview along with the BBC and BSkyB, revealed broadcasters had until January 31 to submit a sealed bid.
Channel 4, ITV, Disney and Sky are all expected to enter bids, with NBC Universal and Turner Broadcasting also expressing an interest.
With such fierce competition, Freeview can expect bids of up to £5m, £4m more than the slots were worth when the free-to-air service launched in October 2002.
Channel 4 is likely to pitch entertainment channel E4 or new gaming channel 9 Live to Castle.
ITV is planning to launch its new interactive gaming channel, ITV4, on Sky later this year. The new channel would sit perfectly alongside its other digital offerings on Freeview, ITV1, ITV2, ITV3 and ITV News.
Disney, which launched ABC1 featuring US sitcoms like '8 Simple Rules for Dating my Teenage Daughter' and 'Home Improvement' on Freeview last year, is likely to put forward the channel. It will then be able to run for 18 hours as opposed to the limited 6am-6pm time slot it currently has on Freeview.
Sky, one of the joint venture partners with Freeview, is looking at expanding its current Freeview portfolio of Sky News, Sky Sports and Sky Travel with a movie or sport offering, although there is talk that it could still go forward with an entertainment channel.
The new channel slot is due to debut on April 1 2005 and the eventual buyer will be tied into an initial 12-month contract.
The news comes as record Christmas sales have increased the number of Freeview households in the UK to 5m, compared with almost 4m at the end of September.
Digital take-up is expected to soar as Sky's FreeSat and Freeview go head-to-head for customers.
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