If SunEntry stops working for you and you get a message that looks something like this:
The work-around is here: http://www.aavso.org/java-security-problem 
The problem is that Java just changed its definition of "high risk" applications to include those with "self-signed" security certificates such as the one the AAVSO is currently using for SunEntry. We are looking into our options for purchasing a certificate from an official "Certifying Authority" which will solve the problem, but in the meantime, the above mentioned work-around should get things up and running again.
Please contact me (email@example.com ) offlist if this does not help.