Using exp/imp utilities if the database size is moderate(exp dump file is within file limits that OS support)

Using Oracle Migration utility.

Refer the following links

http://www.dbasupport.com/forums/sho...?threadid=4236
http://www.dbasupport.com/forums/sho...?threadid=5221
http://www.dbasupport.com/forums/sho...?threadid=5289
http://technet.oracle.com/docs/produ...a86632/toc.htm