There are 2 ways to get a visa for travel to Vietnam.
1. Mail your passport, application form, return envelope and passport sized photo's to the Vietnamese Embassy in the A.C.T (assuming you can't go in person). Pay $75 after 3 days processing they will send back your visa and passport.
2. Visa on arrival which is the option I went for. There are numerous websites that you can pay money to and they will send you and the Vietnamese airport a letter of approval for a visa. I went with http://www.myvietnamvisa.com/. Three days after my order I received an email back from them with an attached multi-page document containing the names of 28 people they had bulk approved for visa.