plastic bags : BioBag

BioBag are a brand of 100% biodegradable plastic bags, made from cornstarch, biodegradable polyester and vegetable oil. They are shelf-stable, but biodegrade in between 10 and 45 days (condition dependent) when exposed to the elements. Biobag have local websites for the USA, Canada, and the UK. In Australia, they are available through Biome.

disposable plates, cups and cutlery : bioware

Bioware is a range of fully biodegradable disposable plates cups and cutlery made from sustainable (non-petrochemical) resources produced by Huhtamaki. Those items I have seen for sale are produced in Taiwan.