Create simple vb.net or c# and php Public/Private key RSA encryption methods.

Am looking for a very simple set of methods: 1: VB.NET or C# based (prefer VB.NET but C# is ok) for: a. Encrypting a string message with a RSA public key b. Decrypting/Verifying a message encrypted with a RSA private key using the public key. 2: PHP based functions to: a. Decrypt a string message with a RSA private key (string encrypted with method 1a) b. Encrypt a string message with a RSA private key (to be decrypted by 1b). I would also like methods for the reverse created as well, in case they are ever needed - VB.NET/C# encrypting with private key and a PHP function to decrypt with private key. I would also like the coder to include instructions on how to secure this communication using a 3rd party public/private key pair. This should be a very simple project for someone with experience in RSA cryptology, but the successful conclusion of this project will lead to another larger project in a related area (application security). This is a necessary first step.