Many coursebooks now have their own Web sites to provide additional activities.
Here are Web addresses for a few of the major ESL/ELT publishers.
Cambridge University Press (http://publishing.cambridge.org/elt)
Heinle/Thomson Publishing (http://www.heinle.com)
McGraw-Hill/Contemporary (http://mhcontemporary.com)
Oxford University Press (http://www. Oup.co.uk)