Update 2 (29-Jun-09): Also checkout Logan Rockmore's little Javascript which promises to be even faster ...
Here's a little script to post the currently selected headline in NetNewsWire (my favourite Mac OS X newsfeed reader) to your instapaper account.
(*
* Submit NetNewsWire headines to instapaper for later reading. See http://www.instapaper.com/
* Create an instapaper account first, select a news item in NNW, then run this script.
* Assumes you're using Safari. Doesn't handle all html entities; works best on English feeds.
* Doesn't check if the submission succeeded, so you need to keep your eyes open. :-)
* -- Bruce Walker <bruce.walker@gmail.com> -- Feb 1, 2008
*)
on unhtml(html)
-- remove markup, convert common entities to ascii (the rest to "?"), nuke blank lines & restrict length
return do shell script "echo " & quoted form of html & "| sed -e 's/<[^>]*>//g' -e 's/ / /g' -e 's/—/--/g' -e 's/‘/`/g' -e 's/“/``/g' -e 's/“/``/g' -e \"s/”/''/g\" -e \"s/”/''/g\" -e \"s/’/'/g\" -e \"s/’/'/g\" -e \"s/'/'/g\" -e 's/&[^;][^;][^;]*;/?/g' -e \"s/'/\\\\\\'/g\" | tr '\\r\\n' ' ' | dd ibs=1 count=192"
end unhtml
tell application "NetNewsWire"
set NNWURL to URL of selectedHeadline
set NNWTitle to my unhtml(get title of selectedHeadline)
set NNWSummary to my unhtml(get description of selectedHeadline) & " …"
end tell
tell application "Safari"
-- submit to instapaper using Safari's saved session/account cookies
set foo to do JavaScript "window.open('http://www.instapaper.com/b?v=3&u='+encodeURIComponent('" & NNWURL & "')+'&t='+encodeURIComponent('" & NNWTitle & "')+'&s='+encodeURIComponent('" & NNWSummary & "'),'t','toolbar=0,resizable=0,status=1,width=250,height=150')" in document 1
end tell
Enjoy!