Create a Twitter Parser

Python, 140

^ 140 chars was actually a coincidence.

def f(s):
 s=s.split();i=0;l=[]
 while s:
  i+=1;t='(%d/%%d)'%i
  while s and len(t+s[0])<140:t+=' '+s.pop(0)
  l+=[t]
 for t in l:print t%i

While there are words left, the solution will create new tweets from the supply of words and append them to a list. For each tweet, it will keep trying to add words until the tweet's length reaches over 140 characters. Two characters are reserved for the total tweets, which are filled in later as each tweet in the list is printed.

Example output:

(1/11) FOUR SCORE AND SEVEN YEARS AGO OUR FATHERS BROUGHT FORTH ON THIS CONTINENT A NEW NATION CONCEIVED IN LIBERTY AND DEDICATED TO THE
(2/11) PROPOSITION THAT ALL MEN ARE CREATED EQUAL. NOW WE ARE ENGAGED IN A GREAT CIVIL WAR TESTING WHETHER THAT NATION OR ANY NATION SO
(3/11) CONCEIVED AND SO DEDICATED CAN LONG ENDURE. WE ARE MET ON A GREAT BATTLEFIELD OF THAT WAR. WE HAVE COME TO DEDICATE A PORTION OF THAT
(4/11) FIELD AS A FINAL RESTING PLACE FOR THOSE WHO HERE GAVE THEIR LIVES THAT THAT NATION MIGHT LIVE. IT IS ALTOGETHER FITTING AND PROPER
(5/11) THAT WE SHOULD DO THIS. BUT IN A LARGER SENSE WE CAN NOT DEDICATE, WE CAN NOT CONSECRATE, WE CAN NOT HALLOW, THIS GROUND. THE BRAVE
(6/11) MEN LIVING AND DEAD WHO STRUGGLED HERE HAVE CONSECRATED IT FAR ABOVE OUR POOR POWER TO ADD OR DETRACT. THE WORLD WILL LITTLE NOTE NOR
(7/11) LONG REMEMBER WHAT WE SAY HERE BUT IT CAN NEVER FORGET WHAT THEY DID HERE. IT IS FOR US THE LIVING RATHER TO BE DEDICATED HERE TO THE
(8/11) UNFINISHED WORK WHICH THEY WHO FOUGHT HERE HAVE THUS FAR SO NOBLY ADVANCED. IT IS RATHER FOR US TO BE HERE DEDICATED TO THE GREAT
(9/11) TASK REMAINING BEFORE US, THAT FROM THESE HONORED DEAD WE TAKE INCREASED DEVOTION TO THAT CAUSE FOR WHICH THEY GAVE THE LAST FULL
(10/11) MEASURE OF DEVOTION, THAT WE HERE HIGHLY RESOLVE THAT THESE DEAD SHALL NOT HAVE DIED IN VAIN, THAT THIS NATION UNDER GOD SHALL HAVE
(11/11) A NEW BIRTH OF FREEDOM, AND THAT GOVERNMENT OF THE PEOPLE BY THE PEOPLE FOR THE PEOPLE SHALL NOT PERISH FROM THE EARTH.

Perl, 51 Characters

s#\G(.{1,132})(\s+|$)#(${\++$a}/~) $1\n#g;s#~#$a#g

Requires -p command line prompt, 1 char included.

Explanation: insert the count portion before and newline after word groups of up to 132 characters. Insert a placeholder (~) for the total, which is then replaced by a second substitution. This breaks if the message contains ~, but one could easily use an unprintable character instead.

It cheats slightly: it always allows seven characters for the count portion, (nn/nn). Really, if it is (n/n) it should allow two extra characters. However, an arbitrary solution to this would greatly increase the complexity of the problem.

Ruby, 77 characters

f=->t{i=0;$><<t.gsub(/(.{1,132})([ \n]|$)/m){"(#{i+=1}/%{i}) #{$1}\n"}%{i:i}}

Packed the logic into a single regular expression. Output of f[text]:

(1/11) FOUR SCORE AND SEVEN YEARS AGO OUR FATHERS BROUGHT FORTH ON THIS CONTINENT A NEW NATION CONCEIVED IN LIBERTY AND DEDICATED TO THE
(2/11) PROPOSITION THAT ALL MEN ARE CREATED EQUAL. NOW WE ARE ENGAGED IN A GREAT CIVIL WAR TESTING WHETHER THAT NATION OR ANY NATION SO
(3/11) CONCEIVED AND SO DEDICATED CAN LONG ENDURE. WE ARE MET ON A GREAT BATTLEFIELD OF THAT WAR. WE HAVE COME TO DEDICATE A PORTION OF
(4/11) THAT FIELD AS A FINAL RESTING PLACE FOR THOSE WHO HERE GAVE THEIR LIVES THAT THAT NATION MIGHT LIVE. IT IS ALTOGETHER FITTING AND
(5/11) PROPER THAT WE SHOULD DO THIS. BUT IN A LARGER SENSE WE CAN NOT DEDICATE, WE CAN NOT CONSECRATE, WE CAN NOT HALLOW, THIS GROUND. THE
(6/11) BRAVE MEN LIVING AND DEAD WHO STRUGGLED HERE HAVE CONSECRATED IT FAR ABOVE OUR POOR POWER TO ADD OR DETRACT. THE WORLD WILL LITTLE
(7/11) NOTE NOR LONG REMEMBER WHAT WE SAY HERE BUT IT CAN NEVER FORGET WHAT THEY DID HERE. IT IS FOR US THE LIVING RATHER TO BE DEDICATED
(8/11) HERE TO THE UNFINISHED WORK WHICH THEY WHO FOUGHT HERE HAVE THUS FAR SO NOBLY ADVANCED. IT IS RATHER FOR US TO BE HERE DEDICATED TO
(9/11) THE GREAT TASK REMAINING BEFORE US, THAT FROM THESE HONORED DEAD WE TAKE INCREASED DEVOTION TO THAT CAUSE FOR WHICH THEY GAVE THE
(10/11) LAST FULL MEASURE OF DEVOTION, THAT WE HERE HIGHLY RESOLVE THAT THESE DEAD SHALL NOT HAVE DIED IN VAIN, THAT THIS NATION UNDER GOD
(11/11) SHALL HAVE A NEW BIRTH OF FREEDOM, AND THAT GOVERNMENT OF THE PEOPLE BY THE PEOPLE FOR THE PEOPLE SHALL NOT PERISH FROM THE EARTH.