Building mailtos

NSString *htmlBody = @"you probably want something HTML-y here";  
  
// First escape the body using a CF call  
NSString *escapedBody = [(NSString*)CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault, (CFStringRef)htmlBody, NULL,  CFSTR("?=&+"), kCFStringEncodingUTF8) autorelease];

// Then escape the prefix using the NSString method  
NSString *mailtoPrefix = [@"mailto:?subject=Some Subject&body=" stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];  
  
// Finally, combine to create the fully escaped URL string  
NSString *mailtoStr = [mailtoPrefix stringByAppendingString:escapedBody];  

// And let the application open the merged URL  
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:mailtoStr]];