Where do you teach? I'm the librarian/tech integration person at C. P. Smith... I find the power of web2.0 tools really gets my students excited to work/learn/think. Voicethread is my favorite tool to use right now; I imagine it would be a great tool for ESL as it is accessible world-wide. Have you had a chance to try it yet?
With your interest in using Education Technology in the classrom, I recommend you take a look at Wiziq's virtual classroom and authorstream's power point presentation platform. Both are web based platforms, have a bunch of features and free basic service.