#iOS5のTwitter.frameworkのサンプル
FNADetailViewController.m
TWTweetComposeViewControllerのサンプル簡単です
- (IBAction)tweete:(id)sender {
    if (![TWTweetComposeViewController canSendTweet]){
        // エラー処理
        return ;
    }
    NSDictionary *shop = self.detailItem;
    TWTweetComposeViewController *tvc = [[TWTweetComposeViewController alloc] init];
    UIImage *image = self.photoImageView.image;
    [tvc addImage:image];
    [tvc setInitialText:[NSString stringWithFormat:@"『%@』 - ",[shop objectForKey:@"name"]]];
    NSURL *url = [NSURL URLWithString:[[shop objectForKey:@"urls"] objectForKey:@"pc"]];
    [tvc addURL:url];
    tvc.completionHandler = ^(TWTweetComposeViewControllerResult result){
        [self dismissModalViewControllerAnimated:YES];
    };
    
    [self presentModalViewController:tvc animated:YES];
}

参照