1. Make sure you have quicktime 7 loaded on your machine (it's on a separate install folder on the operating software, i.e. snow leopard.)
2. Go to Apple's website and buy quicktime 7 "pro" code. (it's actually an unlock code that gives full operation of export using quicktime 7. (Quicktime 10 will not output).
3. in Quicktime 7 (once you begin in the filters button there are settings. Set to colorsync.
4. In FCPX go to share and burn out a prorezz 422 HQ file in the native size as your edit. (in other words if your timeline edit in FCP X is prorezz, 422, 24 fps, 1920 x 1080 those should be your "share" or in real world terms output settings.
5. Once the prorezz file is burned out in it's desired location, open the .mov file in Quicktime 7. (You can put the quicktime 7 icon in your doc and drag the movie icon you've just produced into the quicktime 7 icon.
6. When quicktime 7 opens up with your movie play it to check for errors, color, tone, etc.
7. In quicktime 7 go to the Export function and set it to Movie to quicktime movie.
8. In the Use function don't touch it yet.
9. Go to options button on the right in the window and click it.
10. Another window will open.
11. In this window push the settings button.
12. Another window will open and set compression to H264.
13. Set bit rate from 3900 kps to 5000 kps.
14. Set frame rate to current or 24 fps or 29.7 fps.
15. Set key frame to automatic.
16. Set the compressor quality slider from High to Best.
16. In the lower right hand corner of this window click the blue ok.
17. The next window go to size.
18. Set your size to 1000 px x ? (in other words use a calculator and if your native file is 1920 x 1080, divide 1000 by 1920 which equals .52 (52%).
19. Multiple 52% x your shortest frame size (usually the vertical size of 1080 which mean your h264 output file size will be 562.5 px high, which means your final out put size will be 1000 x 562.5.
20 . Click the blue OK.
21. the underlying window will appear and if your video has sound check the sound box.
22. On sound click settings and a new window will open.
23. For Web set the sound to IMA 4:1, 48mhz and click OK
24. The window will close and the previous window will open.
25. Click box prepare for internet settings.
26. Scroll through and set it for Fast Start Compressed Header (this will allow your video to play on the internet without a website wrapper.
27. click the blue ok
28. The main underlying window will open and decide where you want to put your soon to be transcoded h264 movie.
29. Click the blue save button.
20. Let it process, check it when finished and your good to go.
BTW: This information is available on the web, or spend a fair amount of money and buy Sorenson Squeeze.
BTW2: I think I've covered everything, but try it a few times and also check for color and tone. if too flat Quicktime 7 has a filter setting and you can change contrast etc.