It is very strongly recommended that you disable Java, that it not be working, as it is vulnerable to malware.
Java 7 updated for 10.7-10.8
Released Feb 1, 2013, fixes 50+ security flaws
Download and install
For Java versions 6 and below OS X 10.5-10.6 machines
Apple supplies their own version of Java. For Mac OS X 10.6 and below, use the Software Update feature available under the Apple menu to check that you have the most up-to-date version of Java 6 for your Mac.
Java SE 6 End of Public Updates
After February 2013, Oracle will no longer post updates of Java SE 6 to its public download sites. We highly recommend downloading and installing Java 7.
If your considering upgrading OS X from 10.6.8 to 10.8 via AppStore to run Java 7
Be forewarned no PowerPC based programs or driver software will run any longer.
Check here BEFORE you upgrade OS X!
Alternatives if you must run Java 7
If Apple disabled Java 6 in 10.6, and you can't upgrade OS X to 10.8, then your pretty much done with Java in OS X because Oracle won't issue updates for Java 6 anymore.
However you can install Windows 7 and continue to use Java 7+ there until support for Windows 7 ends in 2020.
If your on 10.6, I very highly recommend the free Virtualbox for the virtual machine software as it gets updates, VMFusion and Parallels have moved on with only 10.7+
Check Software Update...
APPLE-SA-2013-02-01-1 Java for Mac OS X v10.6 Update 12
Java for Mac OS X v10.6 Update 12 is now available and addresses the
Available for: Mac OS X v10.6.8, Mac OS X Server v10.6.8
Impact: Multiple vulnerabilities in Java 1.6.0_37
Description: Multiple vulnerabilities exist in Java 1.6.0_37, the most serious of which may allow an untrusted Java applet to execute arbitrary code outside the Java sandbox. Visiting a web page containing a maliciously crafted untrusted Java applet may lead to arbitrary code execution with the privileges of the current user.
These issues are addressed by updating to Java version 1.6.0_39.
Further information is available via the Java website at http://www.oracle.com/technetwork/java/javase/releasenotes-136954.html