This site discusses the app Explain Everything, which I used to make my first digital storytelling presentation. It is great for a little bit of screen casting on a tablet. The app lets you export as a video as well.
This is a site I have used last year and will start very soon using with my students. There are excellent online simulations for math and science students with comprehensive lesson pages for teachers and students. There is a 30-day free trial as well...
Cue is a professional development company that specifies in educational technology. Although it is a company, there is a great free app for IPads and IPhones where you can download their informational magazines for free.
This is a link to the abstract of an article I found through EBSCO by UCF Associate Professor Dr. Gina Gresham. The study she conducted is about the math anxiety levels of pre-service teachers before and after taking a specialized course on how to teach the subject using tools like manipulatives.
Jamendo is a site where you can download creative commons music for free. It has a number of calming, instrumental tracks that would be perfect background music in the classroom.
PBS Learning Media Home Page has a number of multimedia activities and ideas for lessons. There are some great, short videos explaining definitions as well. The site can be searched by standard, subject or as a whole.