A few weeks ago I did one of these tests and got paid 4000 yen...go to this online form and fill it in. They will contact you about the test after that.
"One of the largest market research companies in Japan, is looking for a selection of non Asian foreigners currently living in Japan, who would be prepared to participate in various market research campaigns on an ongoing basis. Relevant individuals will be paid for their time and/or opinion, depending on the project.
Both men and women may be asked to participate, depending on the project. Please fill out the form below accurately in order to be chosen for the right project and to be paid accordingly.
Current Project: A large Japanese mobile phone manufacturer, wishes to conduct a survey with American and Canadian men and women. The survey will be held on Saturday September 7th and Sunday September 8th in central Tokyo and will take approx 30 minutes."