good resources:
http://webphysics.davidson.edu/physlet_resources/bu_semester2/c13_cyclotron.html by Davidson College
http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=33 by Fu-Kwun Hwang Cyclotron
http://www.schulphysik.de/ntnujava/cyclotron/cyclotron.html mirror of Fu-Kwun Hwang Cyclotron
http://www.phys.uu.nl/~engelb/elkbphyslets/Cyclotron/cyclotron.html mirror of Fu-Kwun Hwang Cyclotron
http://www.aug.edu/~chmtmc/ntnujava/cyclotron/cyclotron.html mirror of Fu-Kwun Hwang Cyclotron
http://egeducation1.blogspot.com/2010/11/cyclotron.html mirror of Fu-Kwun Hwang Cyclotron
http://www.fed.cuhk.edu.hk/sci_lab/ntnujava/cyclotron/cyclotron.html mirror of Fu-Kwun Hwang Cyclotron

http://www.kcvs.ca/site/projects/physics_files/newCyclotron/Cyclotron.swf by Andrew Martin King Centre Visualization in Science http://kcvs.ca
http://www.wainet.ne.jp/~yuasa/flash/EngCyclotron.swf simple animation
http://www.mksfoundation.com/SiteFlash/Magnetism/09_Cyclotron.swf simple animation by MK Srivastava
http://ubpheno.physics.buffalo.edu/~dow/PASI2007/website/Cyclotrons%20and%20Synchrotrons.swf PowerPoint by Drew Weymouth