It's time to think about leaving your laptop at home.

For years, mobile workers have been ditching their desktop computers for laptops that they can take wherever they go. Now road warriors are starting to realize that they can get even more portability -- and lots of computing punch -- from smart phones.

These souped-up cousins of ordinary cellphones, with email and other Internet functions, have become much more powerful in the past year. So powerful, in fact, that they can handle nearly every computing chore that many business travelers need to do, from checking warehouse inventory levels to watching movies on airplanes. Best of all, users can do those tasks with a pocket-size gadget that weighs a few ounces, instead of a five-pound hunk of plastic that goes into a shoulder bag.

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The result: Many travelers are now using smart phones the way they once used laptops -- and laptops the way they once used desktop computers. Mobile workers rely on their laptops to create PowerPoint presentations and do other heavy-duty computing. But then they leave the laptops in their offices, homes or hotel rooms and take their smart phones out into the world -- to client meetings, say, or factory visits.

In some cases, road warriors are going even further, ditching their laptops entirely and doing all their mobile work from smart phones. And many travelers say they'd be willing to take the same step as technology improves -- which it's been doing by leaps and bounds lately.

Faster Internet connections over wireless 3G networks are getting more pervasive. Cutting-edge devices like Apple Inc.'s iPhone are sporting bigger, touch-sensing screens that make it easier to surf the Web. And mobile software is finally getting good enough for users to get their work done when they're on the go.

Carry On

Of course, laptops won't be disappearing anytime soon. Sales of the devices are brisk, and their capacious screens and keyboards will likely remain superior to those on smart phones for a long time, making them the device of choice for creating a presentation or writing an article like this one.

Even doing otherwise simple jobs on a smart phone -- such as extensive note taking -- would drive most users batty. The research and consulting firm Gartner Inc. has actually warned its corporate clients to discourage employees from relying entirely on their smart phones, largely because of the potential for errors and overlooked information when users are editing and reading word-processing documents, spreadsheets and other files on the small screens of mobile phones.

It's little surprise, then, that the number of people ditching their laptops completely in favor of smart phones is small. In a report published in January by research firm In-Stat based on a survey of 1,402 technology users, only 3% of smart-phone users said they rely exclusively on a smart phone when they're on the road. Indeed, 7% of respondents to the survey admitted to some remarkable pack-mule habits, saying they regularly carry two laptops with them -- one each for personal and business use.

Slimming Down

Even so, roughly 52% of respondents to the In-Stat survey said they could envision using a smart phone in the future as their sole computing device, provided handset companies make improvements like better keyboards, expandable screens and applications that work as well as they do on PCs. And it's clear that a sizable number of users already are starting to see their smart phone as a replacement for their laptop for at least some of their needs. In a survey of 460 iPhone users from March by Rubicon Consulting Inc., more than 28% of respondents strongly agreed and 29% mildly agreed when asked whether the iPhone was replacing their use of laptops.

I just bought new laptop a couple of month ago. It will be thing of the past when I use iPhone
for daily computing and even blogging,