On or after Sep 30 2009, TV viewers with a Freeview TV or box (including homes with Top Up TV and BT Vision) will need to re-tune to continue receiving channel Five and a number of other Freeview channels. Satellite, cable and analogue viewers will not be affected. After the re-tune, channel Five coverage on Freeview will increase. Many households will be able to receive Five for the first time from 30 September. A new channel, ‘Quest’, will launch on channel 38 on Freeview. As a result of these technical changes, viewers in areas that have completed switchover who receive their signal from a local relay transmitter will no longer be able to receive ITV3 and ITV4 on Freeview. If you use a Freeview tuner, remember to re-run your tuner set-up in Windows Media Center after noon on Wednesday. The BBC has a video with more details on the switchover.
More info: Press Release