I came across this thread while googling "how to tell if your phone is tapped" and thought I'd share my experiences.
First a little background:
I am a 20 year old artist/college student and am married to a man in the US Navy. He is a nuke on a fast attack submarine, and we are stationed in
Guam and live on a navy base. FYI, I am NOT a Bush supporter, I despise the crooks and neocons in our government, and am seriously considering sailing
away with my husband to an uninhabited island somewhere (there are actually quite a few in Micronesia). In fact, I would have voted for Al Sharpton
had he been the democratic nominee

.
Anyway, we sub wives are not allowed to discuss the boat over the phone because there have been instances at other bases of outside phone taps, and if
we do discuss the boat over the phone and they find out about it, they will restrict boat info to the point where our husbands won't even be able to
tell us when they are going underway or coming back until 24 hours before they leave/come back.
I recently called my sister back in the states (Connecticut), and we were catching up for about 45 minutes and then our convo turned to politics and
the election. We are both staunchly anti-Bush, so our conversation went along those lines, nothing unreasonable, no threats or anything that would
warrant Guantanamo, but all of a sudden I heard a series of loud clicks when there had been none before, and then there was loud static (loud enough
to take the phone away from my ear), and then the connection was lost. After calling me back our political conversation continued as did the clicking.
Finally I just said "Hi whoever's listening, I hope you're enjoying our conversation, but we're not going to say anything to get us into trouble;
we save that for our letters, so now you're going to have to go through our mail!"

We both laughed, but I was serious. After I got off the phone
with my sis, I called my mom, and as soon as the convo turned to politics, the clicking started again, and we were cut off with static AGAIN! Now that
is a pretty big coincidence, don't you think?