A new book called Amazon SimpleDB Developer Guide is a complete guide to using Amazon's SimpleDB database API. This book has a whole chapter on installing memcache to cache your query results locally. CacheLite for PHP is also covered, but the Java section is the weak spot in the otherwise excellent guide.
For example, when tested on a real machine the Java test code showed that the memcached server was running properly, but the Java code for using the cache didn't work. It ran, but continued to query SimpleDB direct. The Python code, however, worked perfectly. However, if you are using memcached in Windows you'll need to use port 11211 instead of what's shown in the book. The section on updating SimpleDB in Python by making serial consecutive calls to SimpleDB is completely missing the code for the script, but the book does go on to cover inserting multiple items concurrently into SimpleDB using a threadpool in Java.