For my own site, I have four form fields on the signup page. Username, Password x2 and an optional email. That, IMO, is actually easier than the twitter flow.

With the twitter flow, I have to click to sign in, then read what permissions you're requesting (from another comment I hear that you aren't requesting permission to tweet for me, which is GOOD), then click to accept.

Since I personally don't require email, the user actually has to give me zero personal information. Using twitter, on the other hand, I have to give you my twitter handle, which might actually be personal information. I don't know how you're going to USE that information, so if it's personal, I'm not sure if that information is going to be shown to everyone in the community or not.