By convention methods with init in their names are constructors. So you create init methods with multiple parameters. The class methods beginning with + are factory methods that return autoreleased objects created with the same init methods with multiple parameters. See the various Foundation container classes for many examples. NSString, NSDictionary and the others all have multiple init methods. Search the headers for "initWith" to find more examples in UIKit.
Also, if you're going to have multiple init methods you should understand the concept of the designated initializer, which you can read about in the Objective C 2.0 language guide.