We have implemented a MIPS simulation environment called WebMIPS. Our simulator is accessible from the Web and has been successfully used in introductory computer architecture course at Faculty of Information Engineering in Siena, Italy. The advantages of the Web approach are immediate access to the simulator, without installation,  and a possible centralized monitoring of students' activity. WebMIPS is capable of uploading and assembling the MIPS code provided by user simulating a five-stage pipeline step by step or completely, and displaying the values of all registers, input and output data of all pipeline elements.