Pass different parameters to an IBAction

Give your various UIButton instances different tag property values.

In your IBAction method -myMethod:, you might then do something like:

- (void) myMethod:(id)sender {
    switch (sender.tag) {
        case (firstButtonTag):
           doFooStuff;
           break;
        case (secondButtonTag):
           doBarStuff;
           break;
        // etc.
    }
}

The values firstButtonTag and secondButtonTag can be stored in an enum if you want to make this easy to maintain.

You can't pass parameters through an IBAction. What I usually do is give the buttons the unique tag in IB. THe tag is an integer value so I u then use a simple lookup table to convert the tag to some value.

In this case, three buttons but tags 1 to 3:

- (IBAction) buttonPressed: (UIButton*) sender
{
    static const NSString* names = { @"Foo", @"Bar", @"Baz" };
    id tag = [sender tag];
    if (tag >= 1 && tag <= 3) {
        NSLog(@"Button pressed is %@", names[tag]);
    }
}

You don't. The only parameter is the sender object, which you may use to have a different behavior, but what I'd do is define 2 action methods, which simply in turn call the same method with a different parameter, i.e. you'd have:

- (IBAction)button1:(id)sender
{
    [self doStuff:kButton1];
}

- (IBAction)button2:(id)sender
{
    [self doStuff:kButton2];
}

- (void)doStuff:(ParamType)param;
{
    ...
}

In defense of that method (no pun intended), I'd add that it makes clearer when you review your UI with Interface Builder to see that different buttons actually have different effects, which is harder to tell if they all call whateverAction: