As far as the jet request goes, try Jon Murchison's BAE 146 series. A search here or anywhere else will come up with a few results.
Most of the subset forums here have tutorials of various sorts located in the top portion (stickies) of that section .
The repainting forum doesn't have stickies, but there is still plenty of info to browse through on the pages:
http://205.252.250.26/cgi-bin/yabb2/YaBB.pl?board=repntFor the water landing effect, the file you locate will be an effects (.fx) file, possibly with a texture file as well. The .fx file simply goes into your FS2004/effects folder and the texture file goes into the texture folder that is within that effects folder.
There are a number of water landing effects available, so all I can say is to try searching for the keywords "water landing", "splash", "waves", etc.
Last edited by SeanTK on Wed Feb 24, 2010 1:23 pm, edited 1 time in total.