You can access Hadoop from many different languages and a number of resources set up Hadoop for you. You could try Amazon's Elastic MapReduce (EMR), for instance, without having to go through the hassle of configuring the servers, workers, etc. This is a good way to get your head around MapReduce processing while delaying a bit the issues of learning how to use HDFS well, how to manage your scheduler, etc.
It's not hard to search for your favorite language & find Hadoop APIs for it or at least some tutorials on linking it with Hadoop. For instance, here's a walkthrough on a PHP app run on Hadoop: http://www.lunchpauze.com/2007/10/writing-hadoop-mapreduce-program-in-php.html