is Feebas can be found by surfing or by using a rod ? (if the answer is rod.. then what rod ?)

Feebas is catched by using a rod. Any rod will do, but the best one to use is the Old Rod, to lessen the chance of encountering any other Pokemon.(Except of course that damn Magikarp.)

-Edit-
Hah! I beat you SST!

You use a fishing rod to get Feebas. It can be any fishing rod, but you're probably better off with the Old Rod.

bah.. just found out i only got good rod.. (^?#$&?@)
where's the old rod ?

Old Rod is in Dewford. Talk to a fisherman there, and he'll give you the Old Rod.

ffs i'm tryin and all i get is a lvl5 Magikarp or lvl8 Tentacool..

I can't believe you wanting to use an old rod instead of a good rod.

An Old Rod gives better chances and plus if you use it and got the wrong pokemon, you'll hardly get hurt and you can run away easier.

silver stone - i got rayquaza.. it's ok :>

I suggest old rod. Feebas will be low leveled, therefore the evolved Milotic will be able to learn some decent moves.

is there some way to catch the f***in Feebas ?!!!
i'm tryin for an hour and NOTHIN

lol u can catch him in 6 tiles and over 400 to choose from so have patience...or use an AR

Feebas may be the toughest in the game to catch. But one hour is nothing compared to what others played to just get him. Some people have done it three straight days and have not found them but that is rare and only if you have horrible luck of skipping over the exact 6 tiles that he is in. Just have patience and you will eventually find feebas sooner or later.

what are the 6 tiles and what's an AR ?

What is meant by saying 6 tiles is this:

When you go one step that is said as one tile. Your character takes up one tile. And so, out of over 400 tiles (of water) on Route 119, six tiles have a chance of you sighting a Feebas.

Also, an AR stands for Action Replay and is a cheating device you can use for different systems including the GBA /SP.