SimplePost creates multipart and urlencoded NSMutableRequests that you can use to post dictionaries of data to your web service and it works with ARC.
As the developer (Nicolas Goles Domic) says it has a simple functionality and no external dependencies. You will have to create your own delegates, etc. This types of post requests should handle several common cases, designed to work with Automated Reference Counting (ARC).
+ (NSMutableURLRequest *) multipartRequestWithURL:(NSURL *)url andDataDictionary:(NSDictionary *) dictionary;
+ (NSMutableURLRequest *) urlencodedRequestWithURL:(NSURL *)url andDataDictionary:(NSDictionary *) dictionary;