Bi-Weekly

http://www.thefreedictionary.com/biweekly

• Happening every two weeks.
• Happening twice a week; semiweekly.

http://www.merriam-webster.com/dictionary/biweekly

• occurring twice a week
• occurring every two weeks fortnightly

http://en.wiktionary.org/wiki/biweekly

• Occurring once every two weeks.
• Occurring twice a week

Here is the bottom line:
The prefix bi- applies to the week rather than to the events that occur, therefore giving the sense of “every two weeks”. But in the UK is means “twice a week”.

For the sake of clarity, it is advisable to use one of the synonyms instead.

Synonyms

• Every two weeks: fortnightly
• Twice a week: twice-weekly, semiweekly

Am I seriously going to start saying fortnightly???