At softpedia.com, you'll find a photo of a 20 Kg mushroom from the Mexican state of Chiapas. It actually looks like a mushroom, only bigger.
Evolutionary Biologist has a lively discussion regarding experiments, new and old, that ask if bacteria get old as they multiply (with a comment by Elio). The question itself is tantalizing because cells that divide by binary fission are generally thought to be "immortal."
At Sandwalk, you'll find a witty and insightful video by Robert Ince on the Top Five Dead Scientists.
One of our favorite fungal blogs, Kathie Hodge's Cornell Mushroom Blog, carries interesting time-lapse movies. A recent one is on "Supermarket Mycology. Flyspeck disease of apples."
In Catalogue of Organisms, Christopher Taylor has an informative piece on mycolic acids of the Corynobacterinaea, which include the diphtheria bacillus, tubercle bacilli,
Nocardia, and others.
Not a blog, but the New York Times has a site for microbiological news. And of course, MicrobeWorld News (links in the right-hand column) is a steady source of this kind of news.