Carriers have been fighting for years to maintain strict control over what they allowed on our cell phones. They rejected innovative ideas that were free or less expensive than what they were able to charge. Developers, who viewed the cell phones as computers, were frustrated by their inability to get their applications onto the phones. The carriers saw phones as closed systems that only they should control.

But finally we're seeing those barriers fall, and we're getting much better products, with capabilities that we could barely imagine a few years ago. And, surprise, the carriers are benefiting as well, with greater demand for their networks and increased sales of phones.

These changes occurred as customers began focusing more on the phones and less on the network, led by Apple's iPhone, and now followed by Google's G1 and BlackBerry devices. These companies are encouraging independent developers to create new applications by offering funding and, most importantly, providing a sales channel through their online stores.

Apple has sold an amazing 200 million applications since its App Store opened on July 11. Many are free or 99 cents, but others cost up to $30. I've installed about 40 different ones ranging from news links and games to productivity applications. These apps can turn a phone into a game machine, an entertainment device, a business phone or a combination of all three. The online stores allow purchases to be made from the phone with just a few clicks, and the app is up and running a few minutes later.

(Apple has the final say on approving what's sold in its store, so it's not completely open like the Google Store. It has rejected some applications, such as one that provides turn-by-turn directions. Some speculate it's because Apple may want to offer that product itself.)

While in a cab on a business trip in New York City last month, I searched the Apple App Store on my iPhone to see if there was a good expense tracker to organize the expenses I was accumulating. I found a number of different programs, each with a description, rating and user reviews.

I downloaded iXpenseIt from FYI Mobileware (ixpenseit.com), designed to track expenses. It had a top rating of four stars and more than a hundred rave reviews.

I purchased it with a single click, was automatically charged $4.99 on my credit card (on record at Apple), and the program was on my phone 15 seconds later, before the cab reached my destination.

After using it for a month, I've been delighted with how well it works. I've found it to be one of the best applications for the iPhone, far better than anything I've used for tracking expenses on my computer. And it's the perfect application for a phone; it's always with me as I incur the expenses. Each expense can be associated by category, sub-category, amount, client, date, location and currency, and can include a note.

You can view your expenses by day or month and create summary reports that you e-mail to yourself. One clever feature lets you take a picture of a receipt using the iPhone camera and then attach it to the item.

FYI Mobileware has just released iXpenseIt 2.0, which lets you also create a personal budget to track expenses and creates reports that tell you how you're doing. It's a great tool during these tough economic times when we're trying to reduce our spending.

While the iPhone was originally positioned as a consumer phone, products such as iXpenseIt are contributing to the phone's popularity in business. A recent J.D. Power survey places the iPhone at the top of its list for satisfaction among business users of smartphones.

I spoke with the founders of the company, Yun Zhang and Henry Jia, located in New York. They told me it took about six months to create the product and then a few weeks to go through the approval process at Apple. Once the iXpenseIt appeared on the Apps store it became instantly available around the world. And for this company, it was significant. The product has become a big seller in Germany and Japan. It's now available in English, Japanese, French, German, Chinese and Spanish.

Zhang thinks Apple is doing things right: "Overall, we feel that it is the best platform out there. We also feel that there should be some control in place to ensure an application doesn't contain any malicious code. It's is the most mature mobile application platform for third party developers since it leverages its iTunes store which has been out for many years. It handles the hosting, change management, distribution and billing."

This is a great illustration of how a flat world works: A two-person company develops a product that's sold around the world, all from a small office in New York.

How does one company make its printer stand out from the rest? Free ink would be one way, but we'll need to wait for that. Epson has come out with a new top of the line 5 in 1 model with Wi-Fi (Print / Copy / Scan / Fax / HD Photos) that some unique new features designed to get us to print more:

• Coloring Books. Now, kids can star in their own coloring books.

Quickly turn photos into personalized coloring book pages without using a computer.

• Personalized Notepaper. Transform photos into customized notepaper at the push of a button. Use your photo as the background on letter-size paper, with or without lines.

• Printable School Papers. Print lined notebook paper or graph paper at the push of a button. Choose from wide-rule or narrow-rule notebook paper and standard or metric graph paper.

$300 from epson.com