>I'm new to .NET.
>I'm planning to use .Net in my future projects.
>I'm confused, should I use VB or C#?
>Why Microsoft introduced both languages?

VB.NET so VB users feel on familiar ground, and C# so that users of Java feel on familiar ground.

Both languages are relatively small, the opposite of VFP which has many commands. The richness and difficulty is in the libraries, which are identical for all .NET languages.