This is what I did to make my IRLP-TWEET Script work again.
description:	This file will post your link status to a Twitter account.

Tips to install irlp-tweet Version from Jan 21, 2009
########################################################
Sign up for a Twitter Account. http://twitter.com/
Most station I see have a user name of IRLPNNNN (NNNN is the node number)
#######################################################

Then create another account on Supertweet.net
Info on that website will help you along. <SNIP>
SuperTweet.net provides a safe mechanism to use Basic Authentication with
the Twitter API in your scripts, from the command-line using tools like
cURL, or other Twitter apps. Simply Sign-up via Twitter to authorize the
MyAuth API Proxy SuperTweet.net Application and then assign a password of
your choosing
(not your real Twitter password) that your applications can use with the
http://api.supertweet.net API.

#######################################################

Download and install the irlp-tweet script onto your IRLP node.
Place in a directory, I used: irlp/custom

The script location is in the files section of the IRLP Yahoo Group
IRLP-Tweet.tgz Version from Jan 21, 2009

http://f1.grp.yahoofs.com/v1/EDMFTh1KxMlPg7mp4o1o874kwNhMaZDBIvg028XSL6ju7YL
nOOursObidre-7OXD1AQpa9nLGO3fNXykOXX9yOchkxk/IRLP-Tweet.tgz

Edit a few lines of code in this script
USERNAME, PASSWORD, USE_CALLSIGN, URL

Example

# configuration section, self-explanatory

USERNAME="irlpNNNN" #Your twitter user name
PASSWORD="NNNNNN" #Your Supertweet password NOT your twitter password
# Change false to true if you want Echolink callsign to be displayed;
# otherwise, Echolink node number will be displayed.
USE_CALLSIGN=true

AND Change the URL .....THIS is what messed me up.....

URL="http://api.supertweet.net/1/statuses/update.xml"

#######################################################
Add the following line to your custom_on AND custom_off script

$CUSTOM/irlp-tweet
################################################

To test the script.

$CUSTOM/irlp-tweet

##############################################

This worked for me, My Twitter now updates when a node connects and
disconnects.

Good luck
Bob W2YMM