Very often I find myself wishing that I could copy text from a tweet I am reading (in the Twitter app) and paste it in, for example, TweetDeck so I can retweet/reply. How do I go about doing this? Prolonged touch does not work in this case, as it does in the E-mail apps.
Outside of email and the browser, you can only copy text from editable text fields, so you can't directly copy text from other people's tweets in the Twitter app.
Install Copy to Clipboard from the Market. This integrates with the 'Share' menu. By sharing a tweet to this app it will copy the text to you clipboard.