If you're having problems with distorted audio in web browsers in Leopard, the problem most likely is due to a bug in Apple's Java 5.0 implementation. The solution is to downgrade to Java 1.4.2 by selecting 1.4.2 in the Java Preferences utility, which is located in /Applications/Utilities/Java. Remember that this utility works on a per user basis, so all users affected need to have their preference changed individually.