Both of these contests close on October 31st:
2009 San Francisco International Competition: This contest, sponsored by the Haiku Poets of Northern California, is for haiku, senryu, tanka, and rengay. There are different prizes depending on the category, but for haiku there are three prizes of $100, $50, and $25. No simultaneous submissions or reprints. There is a $1 entry fee per poem.
IHS International Haiku Competition 2009: Entries for this contest (put on by the Irish Haiku Society) are $4/poem, or seven entries for $25. No previously published poems. There will be three prizes given of 150, 50, and 30 Euros each.
The deadline for the 2nd Annual Basho Haiku Challenge is also October 31st. If you feel like reading haiku instead of writing it, check out the new issue of Chrysanthemum (#6). There are a couple of good haiku by John Martone and Mark Miller, as well as poems by Peggy Willis Lyles, Bob Lucky, and Paul M.