Here's a tutorial, made by yours truly on how to get:
Offside!
Throw the fish to a teammate who then scores within one second.
(Pic, trophy name and info taken from Joystiq)
I'll show you how to get this Trophy with only
2 controllers and by yourself!
-First load up the game and wait out the horrendous loading time.
-When it finishes, load up Multiplayer and pick Windmill as your level, Capture the Fish as your type. Enable teams and allow people to stand in the basket
-Turn on both your controllers
-Pick your character for Player 1 on your 1st controller
-Pick your character for Player 2 on your 2nd controller
-Hold down the PS button on the 2nd controller and got to "Controller Settings". Change the controller from 2 to 3
-Get out of the in-game XMB and return to the game. Now pick your character for Player 3 on your 2nd controller
-Start the game
-When it starts, have Player 3 move all the way to the right, so he's out of the way
-Swap the 2nd controller back to Player 2
-Have Player 1 stand in the basket, while Player 2 stands on the platform to the right of it (or on the small house below it if you have trouble with the platform)
-Make Player 2 throw a the fish in a high arc towards Player 1 (and the basket). Switch controllers mid-throw (not through the XMB, I mean literally, put the 2nd controller down and pick the 1st one up) and have Player 1 catch it in mid-air and throw it straight down right away
If you did this properly, Offside! should pop in the lower right hand corner of your screen, followed shortly by the trophy in the upper right hand corner.
Ending notes:
-I tried doing this with 1 controller, but you'd have to switch controllers through the XMB when you throw and the game won't let you unpause if you do (it only let's the 1st Player unpause)
-The fish can't touch anything or land and fall mid-throw. I tried this first on Whale Restaurant by having Player 2 toss the fish at the wall and having it slip of the ledge, but it didn't count it. That's why I suggest Windmill, as it has nothing to block your shot.