Warning: Cheapskate alert!
Being a cheapskate, I absolutley detest roaming fees, so I'm about to describe my method of enduring a few minor inconveniences to virtually eliminate roaming when overseas. It requires Skype or other VoIP software that can make outgoing calls installed on the Windows Mobile phone, a Visual Voicemail account, (or a VoIP account that will email your incoming voicemail notifications to you) and occasional access to free or low cost WiFi (easier in some countries than others!)
I use YouMail.com's free Visual Voicemail service, which, like all third-party email services, uses the magic of "conditional call forwarding," intercepts unanswered calls before your mobile operator's voicemail can get them and answers them itself. YouMail then emails you the audio of the voicemail as a .wav or .mp3 attachment, and will even email you that you missed a call, along with the name/number caller ID of the caller (if available.) On a trip to Mexico last winter, I disabled cellular data on my phone, and forwarded my phone unconditionally (all calls) to YouMail before leaving the US. (For reasons I'll skip for brevity, you get charged one minute of roaming overseas even for unanswered calls, if the foreign carrier "touches" the call. Forwarding all calls BEFORE you leave the US diverts the call before the local carrier "sees" it, eliminating the one-minute charges.)
In Mexico, before leaving the hotel for each day's misadventures, and after returning each night, I'd stroll over to the hotel lobby (or the adjacent lobby bar!), connect to the hotel's free WiFi, and retrieve my email, including the emails of each voicemail message, (playable in Windows Media by clicking on the attachment) and missed call notifications sent to me by YouMail. Then I'd fire up Skype and return the calls at $0.02/min. Skype rates over WiFi rather than T-Mobile's "generous" $1.49/min. roaming rate, then compose any email replies I needed to write, fire them off and head to the beach or pool. I instructed family members to text me rather than call in an emergency (since the unconditional forwarding prevented incoming calls, but let texts through), then I could call them back immediately if necessary. (T-Mo charges $0.35 for receiving texts internationally- much cheaper than a one-minute call.) You could also leave instructions to text you rather than email in your voicemail's message if that's easier.
Obviously, if you need to be 100% accessible 24/7, this probably won't work for you, (but if so, what are you doing on vacation overseas in the first place?!?) 
But using this method, we at least had the convenience of outgoing telephone service if absolutely necessary (although, since my wife's phone was similarly forwarded, we could only communicate with each other via text!) and minimal to zero roaming charges. The most we've ever spent this way on our annual Cancun vacations was $20, and that was mostly for pay-per-minute WiFi to retrieve email at a resort hotel with no free WiFi. (The last two trips we stayed in a hotel with free WiFi in the lobby only, but it also reached the pool area and outdoor bar.) A lot of people were VoIPing with their laptops, but I was the only one I observed all week VoIPing on my phone!