Sparrow on Wednesday answered a long-standing request and posted its iPhone app ($3, App Store). The mobile version of the formerly Mac-only app brings in a pane navigation metaphor that both draws on apps like Facebook and Twitter; swipes bring in the main navigation for folders and labels as well as quick shortcuts to deal with individual messages. Shortcuts also see a pull down to refresh, swipes to quickly filter down to unread or favorited messages, and swipes to jump through a conversation.
