The mobile agent technology is considered to be very useful for ubiquitous environments. But in order to apply the mobile agent concept to ubiquitous devices, the mobile agent platform should be lightweight because the devices in ubiquitous environments have very limited computing resources. Normally, the ubiquitous devices have J2ME CLDC environments. But this environment has very limited functionality and does not support reflection, dynamic class loading, object serialization, and so on. Therefore, it is very hard to develop the mobile agent platform over the standard J2ME CLDC environments. We have developed the lightweight mobile agent platform, called mMAP, for PDAs with J2ME CDC and have developed the proxy platform, called SAP, for the mobile phone with J2ME CLDC/MIDP. SAP manages the proxy agent, called shadow agent, which is created for each mobile agent in the mMAP. The cooperation between the two platforms allows us to control the mobile agents through the mobile phone.