CrossAES took me over 12 hours of digging to unearth a way to make the .NET's world play nice with mcrypt. Since it took me so long, I decided to bring it to light. I hope this helps someone.
First, include crossaes.vb to your project. For an example on how to use CrossAES in VB, check the VB Fiddle.
First, include crossaes.cs to your project. For an example on how to use CrossAES in C#, check the C# Fiddle.
First, include crossaes.php to your project or paste the contents in your PHP script. For an example on how to use CrossAES in PHP, check the Codepad. Note: Codepad does not have the mcrypt extension, so it displays an error, but it is perfectly valid code tested on my own machine.