Recently, there has been quite a bit of discussion on the various contest reflectors regarding the problem Yaesu FT-1000's have in regards to key clicks.  During any CW contest, it is easy to tell who is using a rig of the FT-1000 family by the clicks propagated by the radio up and down the band.  It has become quite a serious problem, adding to QRM and making it difficult to copy weak signals if someone with such a rig happens to park near your frequency. 
    Fortunately, there currently are two commonly known fixes to the problem.  Tom, W8JI, originally troubleshot and came up with a solution to the problem.  Later, George W2VJN, of International Radio, came up with and currently markets a kit which does almost the same thing.  I will not go into the specifics of either, except to say that I have heard that W8JI's modification is better, although slightly more difficult to install, than the one marketed by INRAD.  One additional note, W8JI's modification may  cause some CW "mushiness" when sent above 40WPM.  As a contester, this isn't a problem for me (or most people for that matter).
    Several months ago, Paul K1PT ran some tests with the FT1000MP which I use in all contests including WRTC2002.  He installed W8JI's modification, running some tests before and after.  The results are remarkable.  While transmitting dits at 40WPM running 100w into a dummy load, he took S-meter readings from a Ten-Tec OmniVI with both narrow CW filters inserted, hooked up to a 10m beam located 80ft away.  He created the below chart.

    It is obvious to see that W8JI's modification made a dramatic reduction in the clicks the FT1000MP produced.  I highly recommend that everyone with a FT-1000 has either W8JI's or INRAD's keying improvement modification installed. During the 2002 ARRL 10m contest, I operated high power, CW only, making more than 2300 QSOs.  I asked for signal reports afterwards, and received nothing but praise from several hams both in the US and Europe.  Although the band was full of key-clicking signals, mine wasn't one of them.  PLEASE install this mod if you haven't already.  If you are not comfortable doing it yourself, get someone else to do it for you.  I love the FT-1000MP and am glad to know my signal isn't one of the problem ones.  I've listed links to both modifications below.  W8JI's page is extremely informative.

W8JI KEY CLICK MOD from his HOME PAGE

INRAD KEY CLICK MOD (scroll down) from their HOME PAGE