I'm currently looking into digital modes. A good reference book on the subject is: ARRL's HF Digital Handbook
by Steve Ford
latest edition published October 1st 2007
For soundcard to radio software try
Dr. Oliver Welp: Amateur Radio Soundblaster Software Collection
or the WD6CNF Web site
to Control your soundcard go to Romac Sound Card Manager
For contest logging try N1MM free contest logger
To find out what digitals modes use what frequencies, go here to start and then tune around that vicinity.
Clubs