I know a few of the major carriers offer this type of service for a monthly fee. I suppose you could look into that, however there's a build in flaw to this model.

If you use a carrier's backup service for your address/contact list, you can only use that with phones from that particular service. For example, you could transfer information from one AT&T Wireless phone to another AT&T phone, but you wouldn't be able to move data from a AT&T phone to a Nextel phone. I've seen some third-party devices out there that will help you move contacts from one service to another, but I haven't seen backup service that will allows for this functionality without manual (hardware or PC software) intervention.

If you've got a Sony-Ericcson phone, you can use Float's Mobile Agent. It's open source. Lets you download/upload your contacts, texts, photos, etc. via bluetooth.

It can also do cool-in-theory but useless-in-practice things like use your phone as a remote control for your mouse or monitor the temperature of your phone battery (???). Oh, I think it'll fade the music and pop up caller ID on your computer if you get a call.

Main page: http://fma.sourceforge.net/index2.htm List of supported devices: http://fma.wiki.sourceforge.net/Supported+devices

I have looked into this opportunity two years ago. here are my research: 1) USA carriers like Verizon offers a service charging $5 a month to backup contact 2) Carriers in China offers for free. But you have to input them first. But you can query your contact book using SMS. I assume their online contact book sync with your Outlook 3) In 3G, there is a mobile contact book XML standard, using which you can sync with any online contact book supporting that standard on 3G network. There are plenty of startups doing that already since it's so simple to implement.

I'm not sure, but I would check out grandcentral.com

try http://zyb.com - easy sync for any phone

iSync on a mac? Or give zyb a try, it's pretty good.

All good answers. The reason I am asking is because we made such a software for java phones ( and we can port it to more phones) and I was wondering if that feature is enough to launch a startup around it. What do you think

Not just the backup.Maybe you can strech it by allowing a user to upload her address book to the site. Then the site automatically links everyone on your phone book to each others profiles and if anyone changes a phone number it has a cascading effect on everyone who is linked with them - this way phones numbers stay current easily. Also, you could offer functionality to send business cards to each other.And maybe even backup text messages. A social network for phones.

hmmm sounds nice.