Here are some helpful legal writing books and manuals that can be purchased online.
A Form and Style Manual for Lawyers by Ian Gallacher. http://www.amazon.com/Form-And-Style-Manual-Lawyers/dp/1594600961/ref=sr_1_sc_1?s=books&ie=UTF8&qid=1332303789&sr=1-1-spell
Just Writing: Grammar, Punctuation, and Style for the Legal Writer by Anne Enquist and Laurel Currie Oates. http://www.amazon.com/Just-Writing-Grammar-Punctuation-Writer/dp/0735549559
Legal Writing in Plain English: A Text With Exercises by Bryan A. Garner. http://www.amazon.com/Legal-Writing-Plain-English-Exercises/dp/0226284182/ref=sr_1_1?ie=UTF8&qid=1329710058&sr=8-1
Plain English for Lawyers by Richard C. Wydick. http://www.amazon.com/dp/1594601518/ref=dra_a_cs_lb_fa_it_P1100_1000?tag=dradis-20
The Lawyer’s Guide to Writing Well by Tom Goldstein and Jethro K. Lieberman. http://www.amazon.com/Lawyers-Guide-Writing-Well-Second/dp/0520234731/ref=pd_sim_b_1
The Redbook: A Manual on Legal Style by Bryan A. Garner. http://www.amazon.com/Redbook-Manual-Legal-Style-Ed/dp/0314168915/ref=sr_1_1?s=books&ie=UTF8&qid=1329710152&sr=1-1