Transforming Sermons http://transformingsermons.blogspot.com/
A Peculiar Prophet (Blog of William Willamon) http://willimon.blogspot.com/
A Steward of the Secret Things http://stewardofthesecretthings.com/
PreachingToday Blog http://blog.preachingtoday.com/
Unashamed Workman (the more recent addition to my list) http://unashamedworkman.wordpress.com/
Theocentric Preaching http://www.theocentricpreaching.com/
Biblical Preaching. http://biblicalpreaching.wordpress.com/
All are quite good. Milton Stanley lists others as well as a preaching blog group in the comments section of my previous post. I recommend you check it out.