Convincing your boss to send you to a conference is easy. Prove your worth, demonstrate value to the company, write a good proposal and commit to reporting back your findings. This post explains how I convinced Monster to fly me from Malaysia to an SEO conference in the US.
Conferences are great networking opportunities, but there are some great hacks that can help you meet more people and get invited to satellite events. Start with a Hit List for people you want to meet, and venture outside of the main events to connect with key people and get the most value for your conference fee.