Pretty easy, once you get it set up.

Make sure you set the options to your preference

API keys available at http://pastebin.com/api

Any issues, let me know!

use F12 to quick paste clipboard (comment out that alias if you use f12 for something else)
alternatively, use /paste
If you would like to choose your post duration, use /paste -l

Enjoy!

/*
######################
#                    #
# Clipboard Paste    #
# By: Jordan`        #
# Find at #Savage_CL #
# on SwiftIRC        #
#                    #
######################

To use this script, you must have a pastebin API key!
go to http://Pastebin.com/api to get one!

After you have one, put in on line 25 in place of KEY_HERE
*/

/*
##################
#                #
#    settings    #
#                #
##################
*/
;Key goes on the next line
alias -l API_KEY return PUT_KEY_HERE
;this option will cause the program to beep twice on success (TRUE or FALSE)
alias -l OPTION_BEEP return TRUE
;this option will cause the program to echo a message on success (TRUE or FALSE)
alias -l OPTION_ECHO return TRUE

alias F12 paste
alias paste {
  var %l
  if ($1 == -l) %l = $iif($input(Paste Duration?,m,$active,Paste Time,N: Never,10M: 10 minutes,1H: 1 Hour,1D: 1 Day,1M: 1 month),$gettok($v1,1,58),1D)
  else %l = 1D
  var %sockname = paste. $+ $ticks
  sockopen %sockname pastebin.com 80
  sockmark %sockname %l
}
on *:SOCKOPEN:paste.*:{
  var %i = 1
  bset -t &post $calc($bvar(&post, 0) + 1) api_option=paste&api_dev_key= $+ $API_KEY $+ &api_paste_private=1&api_paste_expire_date= $+ $sock($sockname).mark $+ &api_paste_code= 
  while (%i <= $cb(0)) {
    bset -t &post $calc($bvar(&post, 0) + 1) $cb(%i) $+ $iif(%i != $cb(0),$crlf)
    inc %i
  }
  var %s = sockwrite -n $sockname
  %s POST /api/api_post.php HTTP/1.1
  %s Host: pastebin.com
  %s Content-Type: application/x-www-form-urlencoded
  %s Content-Length: $bvar(&post, 0)
  %s $crlf
  %s &post
}
on *:SOCKREAD:paste.*:{
  if ($sockerr) .timer 1 0 noop $!input(An error occured: $crlf $+ $sockerr , o,ERROR)
  var %t 
  sockread %t
  if (($chr(44) isin %t) && (date !isin %t)) {
    .timer 1 0 noop $!input(An error occured: $crlf $+ $replace(%t,$chr(44),$chr(58)) ,o,ERROR)
    sockclose $sockname
  }
  elseif (http://pastebin.com/ isin %t) {
    clipboard %t
    if ($option_beep) beep 2 250
    if ($option_echo) echo 7 -a Pasted (URL on clipboard)
    sockclose $sockname
  }
}