Firstly, ignore what everyone else says they don't have a clue. Except muzzy, because he is my hero and I would like to kiss his big hairy face one day.
Alright.
If you want to get started on Object Orientated programming go and learn C#, which isn't highly multiplatform yet, but it makes more sense to a newb than most OO langauges out already. Then I would suggest you learn C++ or Java. I would choose C++ because there are more compilers for it than the other two, it runs on just about anything, any operating system, and has a lot of support. C++ is popular, which is a really good reason to use it. Java isn't to bad either, but C# is very similar, and can do a lot of things that Java cannot.
If you don't want to fuck around with OO programming (I will try and explain the different later[/i] then just learn fucking C. C like C++ has a shitload of compilers, support, and its probably still the most used and popular language on earth. Unix, Linux, VMS, and the bulk of the Windows NT/2000/XP/2003 kernel was written in C.
Object Orientated programming uses objects and classes, which make it easier to put together things like large interfaces, GUIs and such. Objects are things like "Cats" and "Dogs". Languages like C however use functions like "Bark like a dog" and "eat like a cat", or more in the context of computers "draw something on the screen", "print some text", "open a socket to another host, etc". A class in OO programming could contain a miryiad of functions related to that class. And then to make things even simpler you have stuff like namespace.
My suggestion is that you start with an OO language because it can be tricky to learn OO later if your mind is already poisoned with other languages, especially things like BASIC and Visual Basic, which you might as well kill yourself and learn OO in your next life (my first languge was basic, its not my fault, I was 7) and when I tried to learn C++ it was REALLY hard.