Summary: The PaCMAn (Parallel Computing with Java Mobile Agents) Metacomputer launches multiple Java mobile agents that communicate and cooperate to solve problems in parallel. Each mobile agent can travel anywhere in the Web to perform its tasks. A number of brokers/load forecasters keep track of the available resources and provide load forecast to the clients. The clients select the servers that they will utilize based on the specific resource requirements and the load forecast. The PaCMAn mobile agents are modular; the mobile shell is separated from the specific task code of the target application. To this end, we introduce the concept of TaskHandlers which are Java objects capable of implementing a particular task of the target application. TaskHandlers are dynamically assigned to PaCMAn's mobile agents. We have developed and tested a prototype system with several applications such as parallel Web querying, a prime number generator, the trapezoidal rule and the RC5 cracking application. Our results demonstrate that PaCMAn provide very good parallel efficiency.