This year, Tisha B’Av is sunset of August 8, 2011, until sunset of August 9.
Tisha B’Av is a 25 hour fast day (sunset to sunset), but there are other prohibitions on Tisha B’Av that also apply to Yom Kippur:
No washing
No bathing
No shaving
No wearing cosmetics
No brushing your teeth. Eww.
No wearing leather shoes (tennis shoes and flip flops are fine – check for leather soles)
No sexual relations
No studying Torah (You may study the laws of mourning, writings related to the destruction of the Temples, or writings about the other tragedies that have befallen the Jewish people)
No work, in the everyday sense of the word. If you must work, try to wait until after midday.
Minimize your smiling, laughing, and idle chat
Avoid greeting others, such as with “hello” or “how are you?”
We sit on low stools like mourners until halachic midday. You will probably still be in the synagogue at that time.
As for washing, let’s deal with the hygiene issues. You may wash up after using the restroom. If you become soiled somehow, you can rinse it off with cold water.
As for the morning netilat yadayim (ritual washing), the water should only be poured up to the knuckles. You may use that water on your fingertips to rub your eyes if you wish.
I wish you an easy and meaningful fast! Remember to check out Tips to Ensure an Easier Fast!