Make my application multilingual-Collection of common programming errors

How much text are we talking, here? You could always just use case statements that checks a language variable and places the appropriate language then, but this will turn into a mess if you’ve got a TON to replace.

In response to your comment:

Realize that this may not be the best solution, as I’m not familiar with the built in support with .NET.

You can simply keep a variable that contains the language, for example, strLang, and when you’re placing text just have your program run a case statement to output the proper language.

Switch (strLang)
{
 case "EN":
 //OUTPUT ENGLISH TEXT HERE
 break;
 case "SP":
 //OUTPUT SPANISH TEXT HERE
 break;
}

As you can see, it can really clutter your code depending on the number of languages and the amount of text, so you may want to check out the book Randy suggested.