A handout on passive infinitives and another one on the passive_voice with examples and translations.
We all love listening to and watching people. Here is Jennifer ESL in youtube who is explaining the passive.
Explanation with examples of passive forms
Loads of exercises from different sources: Natural English 1, Natural English 2,Natural English 3, Better English, English File, ODL
Or try what other people have bookmarked in Delicious, where people bookmark their favourite links and webs. This one was the best, with explanations plus exercises.