Here's a few more worthwhile books:
The Songwriting Sourcebook
Rikky Rooksby
Berklee, Boston, 2003
0879307498
http://www.amazon.com/gp/product/0879307498
Melody In Songwriting
Jack Perricone
Berklee, Boston, 2000
063400638X
http://www.amazon.com/gp/product/063400638X
6 Steps To Songwriting Success
Jason Blume
Billboard, NY, 2004
0823084124
http://www.amazon.com/gp/product/0823084124
Melody: How To Write Great Tunes
Rikky Rooksby
Backbeat, SF, 2004
0879308192
http://www.amazon.com/gp/product/0879308192
Writing Music For Hit Songs
Jai Josefs
Schirmer, NY, 1996
0825672457
http://www.amazon.com/gp/product/0825672457
Writing Better Lyrics
Pat Pattison
Writer's Digest, Ohio, 1995
1582970645
http://www.amazon.com/gp/product/1582970645
You Can Write Song Lyrics
Terry Cox
Writer's Digest, Ohio, 2000
0898799899
http://www.amazon.com/gp/product/0898799899
88 Songwriting Wrongs & How To Right Them
Pat & Pete Luboff
Writer's Digest, Ohio, 1992
0898795087
http://www.amazon.com/gp/product/0898795087
Song Writing: A Complete Guide To The Craft
Stephen Citron
Limelight, NY, 1985
0879101377
http://www.amazon.com/gp/product/0879101377
The Craft And Business Of Songwriting
John Braheny
Writer's Digest, Ohio, 2002
1582970858
http://www.amazon.com/gp/product/1582970858
Inside Songwriting: Getting To The Heart Of Creativity
Jason Blume
Billboard, NY, 2003
0823083616
http://www.amazon.com/gp/product/0823083616
The Songwriter's Workshop: Harmony [with CD]
Jimmy Kachulis
Berklee, Boston, 2005
0634026615
http://www.amazon.com/gp/product/0634026615
All You Need To Know About The Music Business
Donald S. Passman
Free Press, NY, 2003 (5th ed)
0743246373
http://www.amazon.com/gp/product/0743246373
What They'll Never Tell You About The Music Business
Peter M. Thrall
Billboard, NY, 2002
0823084396
http://www.amazon.com/gp/product/0823084396