One of the main limitations of the current iPhone firmware version is the inability to forward SMS messages and to send a message to mutiple recipients at once. Both of these have been taken care of in a very nice way by the native application weTool and weToolUS (for US iPhones to recognize international format +xxx-...). You can get these by adding the source
http://app.weiphone.com/installer. Version 0.3.6.2 beta that I have tested works quite nicely. The user interface is professionally done. Only, one small issue: it seems that when you forward an SMS to a contact listed the "Contacts" list, the profile of that contact must have the mobile number as the first listed number, otherwise the SMS is never delivered (even though it appears as if it has be sent). Has anybody exprienced this same problem? Other than this small issue, weTool is perfect.
P.S. You can also type directly a number to forward to, you don't have to use the Contacts list.
Many thanks to Aaron Jang and the team that developed this!