Audacity
Audacity is a great free sound recorder that works on both Mac & PC. It is very easy to navigate for young children.
Jing Project
Jing is a fabulous free tool for creating how-to cards for students in the Early Years. Jing allows you to take screen shots and annotate them.
Tip of the Iceberg
Keri-Lee's blog has posts which outline her experiences as a tech facilitator. There are a number which look at the Early Years specifically.
Voicethreads
Voicethreads have numerous possibilities in terms of sharing students' work, ideas and opinions. Definitely worth checking out.