I have built a system using arduino and Ethernet shield. It gets rgb values through URL and changes an rgb led's value. Today I bought an ESP 8266 12E. I want to change to wifi but I cannot find an arduino library that uses spi to connect the arduino to the ESP. I do not want to use only the ESP. Do you know any libraries to do the job or any tutorials.
The following link is a great resource for learning how to use the WiFi module. It has all the commands you are likely to need. The guide is written with the intent that the user will use the module as a standalone device without the Arduino, but at the end of the guide the commands given are all the same. This is the reference I use for projects like this. ESP8622 Quick Start Guide