The following sound files are licensed under the Creative Commons: By Attribution 3.0 
from http://soundbible.com/
boo_heavy2.wav (Crowd Boo And Heckles-SoundBible.com-583263588.wav)
boo_light3.wav (portion of Sports_Crowd-GoGo-2100314571.wav)
cheer_heavy8.wav (portion of Sports_Crowd-GoGo-2100314571.wav)


"Take Me Out to the Ballgame"
Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 3.0
http://creativecommons.org/licenses/by/3.0/
(stretch2.wav, converted from Ballgame.mp3)

Public domain sound effects, from http://www.mediacollege.com
ooh6.wav (crowd-groan.wav)
ooh7.wav (crowd-groan-02.wav)
boo_light4.wav (portion of boo-crowd-01.wav)
rally14.wav (portion of boo-crowd-01.wav)
boo_heavy3.wav (boo-crowd-02.wav)
cheer_heavy9.wav (cheer-hooter-01.wav)

From freesound.org:
S: Fenway Park Sep 19 2010.wav by vflefevre -- http://www.freesound.org/people/vflefevre/sounds/166220/ -- License: Attribution (used as ambient2.wav)
S: baseball sounds.mp3 by bowlingballout -- http://www.freesound.org/people/bowlingballout/sounds/58596/ -- License: Creative Commons 0 (parts used as cheer_heavy11.wav, ambient7.wav, ambient8.wav, 
S: WALLA_Ballpark Organ Cheering Charge by AshFox -- http://www.freesound.org/people/AshFox/sounds/191928/ -- License: Attribution (rally8.wav)
S: crowd noise.wav by LS -- http://www.freesound.org/people/LS/sounds/22380/ -- License: Attribution (used as ambient1.wav and ambient9.wav)
S: WALLA Ballpark Applause Short 04 by AshFox -- http://www.freesound.org/people/AshFox/sounds/191911/ -- License: Attribution (used as cheer_light10.wav)
S: WALLA Ballpark Applause Short 03 by AshFox -- http://www.freesound.org/people/AshFox/sounds/191912/ -- License: Attribution (used as ooh8.wav)
S: WALLA Ballpark Applause Short 02 by AshFox -- http://www.freesound.org/people/AshFox/sounds/191913/ -- License: Attribution (used as cheer_light9.wav)
S: WALLA Ballpark Applause Short 01 by AshFox -- http://www.freesound.org/people/AshFox/sounds/191914/ -- License: Attribution (used as cheer_light8.wav)
S: WALLA Ballpark Cheer Short Foul by AshFox -- http://www.freesound.org/people/AshFox/sounds/191916/ -- License: Attribution (used as foul1.wav)
S: WALLA Ballpark Chatter by AshFox -- http://www.freesound.org/people/AshFox/sounds/191917/ -- License: Attribution (used as crowd1.wav)
S: WALLA Ballpark Clapping Pattern by AshFox -- http://www.freesound.org/people/AshFox/sounds/191919/ -- License: Attribution (used as rally9.wav)
S: WALLA Ballpark Let's Go Organ by AshFox -- http://www.freesound.org/people/AshFox/sounds/191923/ -- License: Attribution (used as rally10.wav)
S: WALLA Ballpark Organ Take Me Out to the Ballgame by AshFox -- http://www.freesound.org/people/AshFox/sounds/191927/ -- License: Attribution (used as  stretch3.wav, and stretch4.wav)
S: WALLA Ballpark Organ Music Various by AshFox -- http://www.freesound.org/people/AshFox/sounds/191929/ -- License: Attribution (used for ambient3.wav, ambient4.wav, and rally11.wav)
S: Play Ball!.wav by CGEffex -- http://www.freesound.org/people/CGEffex/sounds/101137/ -- License: Attribution
S: Play Ball! v2.wav by CGEffex -- http://www.freesound.org/people/CGEffex/sounds/101135/ -- License: Attribution
S: Play Ball! v3.wav by CGEffex -- http://www.freesound.org/people/CGEffex/sounds/101136/ -- License: Attribution (used as rally12.wav)
S: Bat Hit 9 FF095.aif by martinimeniscus -- http://www.freesound.org/people/martinimeniscus/sounds/162886/ -- License: Creative Commons 0 (used as hit_normal3.wav)
S: BaseballHitAndCrowdCheer.mp3 by AmishRob -- http://www.freesound.org/people/AmishRob/sounds/214989/ -- License: Attribution (used as hit_normal4.wav and cheer_heavy10.wav)
S: yells.mp3 by jasinski -- http://www.freesound.org/people/jasinski/sounds/18365/ -- License: Creative Commons 0
S: bb-clapRhm.mp3 by jasinski -- http://www.freesound.org/people/jasinski/sounds/18364/ -- License: Creative Commons 0 (used as rally13.wav)
S: baseball organ by treblebooster -- http://www.freesound.org/people/treblebooster/sounds/151373/ -- License: Creative Commons 0 (used as ambient5.wav)

http://www.freesfx.co.uk
hit_normal3.wav
ooh9.wav
boo_light5.wav