Very true. I didn't mean open source is the only way.
Code reviews, extreme/paired programming, personal discipline, and lots of experience on development teams are also great ways. I'm sure there are others too.
These all are very good points but well written code is not easy to find and tools which help one to quickly understand code become really important in such cases.
In my experience, I've found that processes that influence the desired behavior (through the use of incentives) have been more effective than tools. But I'm certainly no expert and am always looking for better ways to do things.
Have you used any tools that you've found to encourage well written code? I'd really love to give them a try.
I agree to your point that that we need to write more understandable code(whatever the influences may be). By tools I meant some application which would help me understand already available code (well written or otherwise). Something which would quickly let me jump into the code and start working even when I do not have any background information about the code base.
Code reviews, extreme/paired programming, personal discipline, and lots of experience on development teams are also great ways. I'm sure there are others too.