BETWEEN LANDLINES, smartphones, virtual phone systems and voice over Internet protocol services, the competition for a small business's communications dollars is fiercer than ever. And while this healthy rivalry has resulted in everything from free long distance, to cheaper local calls and wireless minutes, small-business owners are still feeling the pinch each time they open up those monthly phone bills.

The reason? People are simply just spending more time on the phone, says Bill Hughes, a principal analyst at In-Stat, a market research firm in Scottsdale, Ariz. “Over the last 10 years, the cost per minute of air time has been declining 30% per year, but the minutes of use have been increasing between 25% and 30% per year.” Users also want more from their service, he says, and therefore sign up for more comprehensive data packages that can add an average of $25 to $30 per user onto the monthly tab.

Here are a few ways small businesses can rein in unruly phone bills — without sacrificing service.

Ditch unused lines and numbers

Small businesses can easily lose track of the number of phone lines that they own. Beyond telephones, there may be lines for fax and credit-card machines, modems, alarms and even time clocks. So the first task is to match known lines to the ones you're paying for, says Barbara Clements, president of Auditel, a telecommunications and expense management firm in Florissant, Colo. If some lines or numbers appear to go nowhere, contact your provider and have them cut off, she advises.

Also, if you have a fleet of mobile employees, landlines may do nothing more than “tell them where their desks are,” says Hughes. In this case, just do away with those phone lines.

Get rid of unused services

Maybe you thought you needed call forwarding and conference capabilities when you signed up for that phone package, but, as it turns out, you really don’t. Either way, you’re still paying for those features, says Mark Braverman, a cost reduction consultant, at Alliance Cost Containment in Louisville, Ky. For both landlines and wireless plans, go through the features you've never (or barely) used and get rid of them, he says.

Look for billing errors

Phone companies aren't infallible so keep an eye out for billing mistakes, suggests Clements. For instance, you could be getting charged for text messages even though you have an unlimited messaging plan. Also, check for charges for duplicate services or services you didn’t even sign up for.

For help, enlist a cost containment or telecommunications auditor who can pick out billing and taxation mistakes, as well as overcharges. They can also negotiate with your provider for any refund or discounts due to the business. The good news is that these firms only receive payment if you see savings. Their cut: usually about 50% of whatever they save the business.

Save on calls

It seems like a no-brainer, but be sure to use toll-free numbers whenever possible. Why dial "411" from your cellphone and get charged a dollar or more, when you can get the same information services for free by dialing 1-800-free411 or Google's (GOOG) 1-800-GOOG-411?

To take the bite out of international calls, sign up for a VOIP service such as Skype. Or, if your company makes a large number of calls abroad, try a web- or videoconferencing service like those offered by ACT Conferencing and Cisco's (CSCO) WebEx. (For more on videoconferencing, click here.)

Shop around

Before you sign a contract, visit sites like BuyerZone to compare quotes from various phone system vendors. After doing some digging, many small business owners might find virtual phone systems to be their most affordable option. These web-based services are hosted by a third party provider, require little hardware beyond a handset and can cost as little as $10 a month. Here’s how it works: service providers such as GotVMail and Virtual PBX host servers that route all calls to the business owner's phone through an Internet connection, allowing them to route a business' calls to whatever destination is necessary. Not only that, but they also offer a range of features including toll-free and local numbers, customized greetings and voicemail services.

Pool minutes

Some employees use a lot more minutes than others. As such, it doesn't make sense for everyone to have individual plans offering the same amount of minutes, says Clements from Auditel. Instead, pool everyone's minutes together. That way, the less phone-reliant in the office won't waste minutes and the heavy talkers won't weigh down your bills. “It keeps your overages and underages streamlined,” she says.

Negotiate with your provider

Wireless companies introduce new plans all the time and, sometimes, switching can save your business a lot of money. Touch base with your provider, say, once every three to six months, to see what their latest offerings are, advises Braverman from Alliance Cost Containment. Just make sure to wait until your business has used up over a year of its contract before attempting to make the switch. “Carriers will be less willing to negotiate when you have two years left on your contract,” he says.

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