Your tweet must have all of the following pieces to be considered valid:
@pixifi
http://bit.ly/Pixifi
#pixifi

Example:
@pixifi the best web-based studio management tool for photographers http://bit.ly/Pixifi #pixifi



Official contest begins March 1st, 2010. Winners will be announced on September 30th, 2010. To be eligible winners must be 18 years of age or older and have participated by tweeting valid tweets described by the rules. Valid tweets also must be non derogatory, non defamitory, and promote pixifi in a positive manner. Rules and announcement dates are subject to change at any time without warning and without reason at our sole discretion. One (1) Grand prize winner will win a full year (1 year) of pixifi service and will be chosen at random from among all entries on September 30th, 2010. Five (5) runner up winners will win six (6) months of pixifi service. Odds of winning depend upon the number of eligible entries received. Prize is one full year of pixifi service starting on winner announcement date and ending exactly one year from that date. Prize can not be exchanged or traded. Prize has no cash value or trade value. This promotion is void where restricted, taxed or prohibited by law. Winner, by accepting the prize, where lawful, agrees to allow the use of his or her name and twitter screenname for advertising and public relations purposes without further compensation.