Information on wireless providers furnished by CTIA – The Wireless Association.
- There are a number of different resources for customers planning to use their wireless devices while traveling internationally . This site includes information on how to get the best international voice and data rates based on destination, and offers tips and tutorials for customers traveling abroad, including:
- Customers may call customer service at any time to block international roaming.
- iPhone users can track data usage overseas by using the device’s Usage Tracker option.
- Information about travelling internationally with a Sprint phone .
- Information on International Voice .
- Information on International Data .
- There are several ways to check balances.
- Using the phone itself (#min#, #msg#, #bal#)
- Calling into IVR (voice recognition service)
- Calling customer service
- Going into dealer or store
- Internet. 
- Users are able to monitor Data Use.
- Customer’s home page is free
- Warning message is sent the first time a customer accesses the web. Message also sent to account holder: “CAUTION: Charges while roaming are higher for voice, web, email & applications.”
- View International roaming and general information  and see “Calling from other countries."
- For information on what to do before you travel, go to "Things to know before you go" under "Calling from other countries" on the same website.
- Access country-specific voice, text, and data rates from a number of sources:
- Website – Verizon Wireless provides customers a single website where they may access the voice, text, and data rates  for almost every country as well as other information regarding international services.
- Quarterly Customer Booklet – Verizon Wireless publishes a quarterly consumer booklet containing extensive information about the companies devices, services, and plans, entitled “Your Guide,” that is available to all customers who activate or renew in stores or via telesales. “Your Guide” provides information on how to obtain service and rates while placing or receiving calls or data in foreign countries.
- Customer Service – Customers can contact the company’s Customer Service via a toll-free number to obtain information about service options available to them while traveling.
- Real-time alerts regarding international usage.
- Verizon Wireless sends a free text message to customers when they turn on their phone in a foreign country welcoming them to the country, providing dialing instructions for calling from that country back to the U.S., and sending them the 24/7 customer service number for global customers.
- If the customer is located in a CDMA country, Verizon Wireless also provides the customer with the data roaming rates for that country.
- Mobile Broadband customers using VZ Access Manager and operating their device outside the U.S. must click-through a disclosure screen providing information about potential data charge rates before being allowed to connect.
- Verizon Wireless allows customers to control their international data usage by shutting off data services on their handset, thereby preventing international data roaming.
- e-office Mobile Data Alerter  allows consumer to monitor data usage and also allows consumer to set up specified alerts based on usage. Built in is an application viewer as well, so the consumer can see what applications are currently running.
- Mobile Minutes Tracker Premium
- Current minute balance
- Rollover minutes
- Data plan balance
- SMS use
- Bill details
- Previous payments
- Overcharge protection alerts
- http://appworld.blackberry.com/webstore/content/2617 
- MyWireless Application to track minute, message and broadband usage: Go to iTunes Store  at the lower right of the page, and search "att mywireless mobile”
- Travel tips
- Turn data roaming “OFF”: Be sure to download and install the latest version of iPhone software from iTunes. To turn data roaming “ON/OFF” tap on Settings > General > Network > Data Roaming
- Utilize Wi-Fi instead of 3G/GPRS/EDGE: Wi-Fi is available in many international airports, hotels, and restaurants to browse the web or check e-mail. You can also use VoIP services (e.g. Skype) to make calls.
- Turn fetch new data “OFF”: Check e-mail and sync contacts and calendars manually instead of having the data pushed to your iPhone automatically. This way you can control the flow of data coming to your iPhone. To turn off the Auto-Check functionality tap on Settings > Fetch New Data, change Push to “OFF” and select to Fetch Manually.
- Consider purchasing an international data package.
- Reset the usage tracker to zero: When you arrive overseas, access the usage tracker in the general settings menu and select reset statistics. This will enable you to track your estimated data usage. To reset Usage Tracker to Zero, tap on Settings > General > Usage > Reset.
- Do not download video on your iPhone or lap top while traveling. This will help you avoid some of the most expensive data charges. If you want to stream a movie, music video, or TV show on your phone, go to a Wi-Fi hotspot and download movies over that network.
- Netcounter Application  keeps track of data usage on mobile phone and provides for exceeded limit alerts.
- For T-Mobile Users
- T-Mobile My Account App for Android : allows users to track minutes and messages used/remaining and bill summary.
- Minutes Tracker for Android : allows user to keep track of T-Mobile cellular minutes, available.
- “Free My Account” application  allows T-Mobile users to choose to receive free minutes usage alerts, over-limit alerts, payment reminders, billing summaries, etc.