I've just connected a pretty cool bunch of web services to solve a pretty simple problem: I want to be able to quickly and easily and cheaply use my cell phone to let my friends in Chicago know where I am and what I'm up to. I want people to be able to spontaneously decide to join me when I'm wandering around the city having fun.
For instance, tomorrow (Thursday) I'm going to go to Blues Festival and wander around. I'd love to be able to send out messages to friends and let them know when I get there and when I move from one part of the fest to another. And as a side effect I'd like to have an archive of all those little updates that'll form a picture of my days, a quick easy replacement for blogging.
Twitter - What are you doing?
Note that when you try to connect twitter to GTalk, it'll fail without an error message. This is a known problem at twitter and they're working on it as a matter of high priority.
However if you want to do some more advanced things or if you have a pre-paid cell phone plan that won't work with twitter there are some cool other tools you can use. Note that for much of this to work you'll need an unprotected public twitter feed so you'll want to consider only twittering updates that you don't mind the world reading.
Twitter has an official application on Facebook. You can configure this application to update your status message as soon as you post a new tweet. You can also use it to see which other Facebook friends are twittering. This is a great way to get your tweets out in real time to friends who aren't on twitter.
This application asks for your twitter password and normally I would be upset about providing a third party password to a FaceBook application but I feel ok doing it when the third party service is the official owner of the Facebook application and all the info on that application is meant to .
Loudtwitter - Twitter feed -> LiveJournal
I LOVE the security model of loudtwitter. You can use this service without having to trust LoudTwitter with either your twitter password or your LiveJournal password. It uses OpenID so you can log into LoudTwitter without having to create an account there. Then you can configure it to use LJ Emailpost to post the messages. Don't forget to add firstname.lastname@example.org to "Allowed sender addresses" in your Mobile Post Settings.
You can customize LoudTwitter to add tags, mood, etc to your message using LJ headers.
I used the following for "text to add at the beginning of the post:"
and for "text to add at the end of the post:"lj-tags: twitter, loudtwitter, web2.0 <lj-raw>
<p>From <a href="http://twitter.com/zarfmouse">twitter.com/zarfmouse</a>.</p>
TwitterMail SMS -> Twitter Feed
Unfortunately my T-Mobile ToGo prepaid cell phone won't work with SMS "shortcodes" so I can't use Twitter's built in SMS integration. Luckily, almost every cell phone provider does SMS->Email gatewaying. So if you send an SMS to an email address (rather than a phone number), it'll get delivered to the right place. Try it!
TwitterMail will give you a special secret email address. When you send an email to that address it'll get posted to your twitter. Unfortunately you will need to give TwitterMail your Twitter password which is not something I'd normally recommend (since TwitterMail is a third party), however your twitter is a public feed with very little sensitive information so the cost of being hacked by the owners of TwitterMail is very low.
Now if you store the special secret TwitterMail email address in your phone's contact list, you can quickly and easily send an SMS to that address and it'll go instantly to your twitter feed. This also bypasses the possibility that Twitter could in the future charge a premium rate for their built-in SMS service.
RSSFWD - Twitter Feed -> Cell Phone
If your phone doesn't work with Twitter's built in SMS service there will still be one piece of the puzzle missing. You want to get updates from certain friends sent directly to your cell phone so you can have up to the minute status updates. This could be useful if you want to keep track of where I am when I'm wandering around the city so you can arrange to join up with me.
First determine the email address of your phone.
Next determine the RSS Feed of the twitter feed you want to send to your cell phone. Mine is http://twitter.com/statuses/user_timeline/14985659.rss.
Then just go to RSSFWD and enter the feed URL and submit. Use text only messages (there's a checkbox for this). When it asks you what email address to subscribe you should NOT use your cell phone's email address directly. Instead you should use your gmail account or some other account that lets you set up a custom filter.
Then in your email program (e.g. gmail) set up a filter so that messages from rssfwd get forwarded to your cell phone. You could get arbitrarily clever with this and subscribe your email address to ALL your followed twitter feeds but only forward certain ones to your cell phone.
The reason for the filter-forward step is so you can easily use the "unsubscribe" link provided in each rssfwd message.
Remember you only have to do this part if the normal Twitter SMS integration does't work because you have a pre-paid cell phone.
ETA: I'm testing this right now and it seems there is a pretty significant delay between when a twitter post is made and when an RSSFWD email goes out. This is unfortunate.