I have recorded famliy photos onto DVD using Pinnacle and other programmes but cannot play them on my new Daewoo DVB-T VCR/DVD Recorder. Is there any freeware I can use to convert my DVDs to a compatible format?

You first may need to download additional codecs. Codecs are required to encode and/or decode (play) audio and video. One such freeware application is the K-Lite Codec Pack 5.8.3 which can be found here:
Free-Codecs.com : Download K-Lite Codec Pack 5.8.3 FULL, K-Lite Codec Pack 5.8.3 STANDARD, K-Lite Codec Pack 5.8.3 BASIC : K-Lite Codec Pack is a collection of codecs and related tools

As far as DVD conversion freeware/software is concerned, you may try this link:
Products of Any Video Converter, DVD Converter, DVD Ripper, DVD Cloner to convert AVI to MPEG, video to iPhone, video to iPod, Zune, PSP

Hope this helps.

Many thanks for your kind help.
glis-glis