The ISE offers a huge collection of language templates.

Your free to copy the text into your source code.

The content can't replace a textbook but once your learned the basic of VHDL will it be a good help.

 

The VHDL - Synthesis Constructs - Flip Flops

Example code: 4x1 Multiplexer with process

Conversion Functions

Asynchronous Input Synchronization (in order to reduce Metastability and Hazard)

Debounce circuit