MyToday.com provides free, instant, e-mail alert notifications via SMS. I discovered this just a week ago, although it existed since quite long and many of my friends were using it and me being totally ignorant about it!!!
To use the service, you just need to carry out the following two steps:
1. Send an SMS to 575758 with the following text MAIL START <your city name>
For example: MAIL START DELHI
MAIL START CHANDIGARH
If you live in a small city/town, then you may send your state's capital city name.
2. The next step is to login to your e-mail account and set an autoforwarder that sends every incoming mail to 91<ur 10 digit mob. no.>@m3m.in
Now whenever any e-mail arrives in your inbox, your mail provider will forward a copy of it to mytoday, and they'll in turn send it to you immediately through SMS.
There are several applications of this service. It depends on your thought power and creativity to tap them. One simple one is instant sms alerts for orkut scraps.
For that, just login to your orkut account from PC and click settings. There in notifications set scrap notifications to be sent by e-mail. And thats it!!! Now, whenever anyone scraps you, you'll immediately receive an SMS.
This service is absolutely free, except for the first activation SMS that you sent. Airtel charges Rs.3 for that. I dunno about other operator charges.