The VisualVM which comes with jdk6 has a basic profiler inside it.
VisualVM is provided with the jdk, so if you have the jdk6 installed, you likely have it installed as well.
If you are looking for a no-frills, easy to use open source profiler, you may want to take a look at Jip (Java Interactive Profiler). It's published under a BSD license. I found it to be quite useful for small programs. At least, the results it gives are way more easy to understand than hprofs output.
Java Mission Control, it's free to use for development and it integrates with Eclipse. It has very low overhead (<1%) since it piggybacks on the data the JVM is gathering anyway.
It's very easy to use and it can also give a lot information you typically won't find in other profiling tools, e.g. latency profiling, online memory inspection, detailed gc statistics
This project is a low overhead sampling profiler for Java that does not suffer from Safepoint bias problem. It features HotSpot-specific APIs to collect stack traces and to track memory allocations. The profiler works with OpenJDK, Oracle JDK and other Java runtimes based on HotSpot JVM.