Now that the dust is settling over Lion and iOS 5, there are a large amount of questions that had been asked in the past that had either a workaround or a not-quite direct answer, but now there is a very direct answer.
Under Snow Leopard and previous, this was not a direct answer, though using URL as tweetie:@username is really ingenius. IIRC the official Twitter for iPhone app supports twitter:username, but I digress.
As of Lion and iOS 5, there is now a first-tier field for Twitter (and Facebook, and Flickr, and LinkedIn, and even MySpace). A user has answered the question directly (admittedly with quite poor quality), but if this question is edited and really updated.
This is rather simple: Use iMessage is a great answer. Not necessarily any different than mine, simply meaning, the best answer is some sort of direct text communication. But iMessage is almost guaranteed to be there, and is easier to set up than e-mail accounts of chat networks.
I know moderators are not supposed to deal with answers, even if they are factually wrong, so I assumes this also means they cannot un-accept the current answer.
Is there another answer besides the obvious (but unreliable):
Hope the OP comes back, or, hope the user with the accepted answer updates their answer?