The latest rumor is the Nextel is looking to sue Verizon over its new push-to-talk service that was launched yesterday. The problem is said to be over the use of "push-to-talk", a phrase Nextel says it trademarked a few months ago. Verizon maintains that such a common phrase should be "open for public use".
The two companies have had a little history--Verizon went after Nextel for "espionage" back in June.