A "good programmer" should be able to pick up any language in no time. There are many different languages in use today.
You should pick one language, learn it inside out, and that'll set you up pretty well. If you learn C++, you'll pick up C easily (NOT THE OTHER WAY AROUND!!1! - DO NOT LEARN C BEFORE C++), and you'll also be able to have a stab at C# and Java.
Visual Basic (and .Net) are very different, but again you should be able to pick these up if you just follow through the code, it'll fall into place.
The older languages like BASIC, PASCAL, FORTRAN, COBOL etc. all follow the same principles, they're just more dated now.
There are several key programming principles which feature in all languages (variables, loops, if statements etc), just each language deals with each differently, and has a different syntax. If you can nail these, you're sorted.
Master of common sense. If you don't like it, stop reading.