Java Security

Hello All,
For the past days I have been scraping through the different posts in this forum. Excuse me if I have missed answer to questions posted similar to mine or have not been able to comprehend it. I am using SUN and SUNJCE provider with JDK 1.3 and I have downloaded JCE 1.2. Also I am in Autralia so any restriction in terms of using cryptography let me know or guide me to source where i can get answers.

It seems for Asymmetric Public Key encryption the best way is to Sign a message with Ones Private Key and then decrypt the message and digest with Receivers Public key. The receiver will use it private key to decrypt the content and then through the Public Key it will identify the sender(Verify). What I have done is I have generated two set of keys using Key generator and providing the algorithm name as parameter.
Now first question is which Algorithms shud I use for encryption and which one for signing.
Becase Currently I get NosuchAlgorithm exception when I Pass DES in the KeyPairgenerator getinstance method. And I get NosUchAlgorithm Excpetion when I use DSA in Cipher.getinstance method. The keys are generated without any fuss.

Any help will be awarded I guess with my appreciation and Thanks and may be duke dollar :-)

Thanks
Javed