Below is a list of some of my favorite sources for finding new No Registration Web 2.0 tools.
Educational Technology and Mobile Learning (Med Kharbach): Educational web resources and mobile apps for teachers and educators
Free Technology for Teachers (Blog by Richard Byrne): Blog provides information on free classroom resources many with video explanations Richard Byrne's video tutorials on YouTube
ilovefreesoftware - Web Applications: Searches for free software, tests, explains basics, reviews, and provides link to the website. Not educationally based but offer some great links.
MakeUseOf: Daily blog covering cool websites, how to's, computer tips, apps, technology, etc.
Teacher's First Edge: Safe Web 2.0 in the Classroom: Evaluates with in the classroom suggestions
Come visit MY list of No Registration Web 2.0 tools