I'll second what everyone else has said - it's not a bad thing at all. It's nice to know things off hand, and eventually you'll find yourself having to look things up less and less. Plus, libraries - and even languages to a lesser extent - are changing all the time, so it's hard to keep it all in mind.
The important thing IMO is that you at least have an idea of what you're trying to accomplish. That's the harder part most of the time. Syntax and APIs are easier to figure out with a quick search.