Based on the recent news in another thread that I can import a cellphone through the mail, I am weighing the whether I want to fork up an extra $13 for a dual sim phone.
According to cnet.com one advantage for owning a dual sim is the following:
Let's say that you're going to Greece on vacation. You want to take a phone so you can keep in touch with local friends and traveling companions and still be reachable by your family back home. Traditionally, you had two choices: either use your existing number and pay expensive carrier roaming fees or take an unlocked handset and pair it with a Greek SIM card. Each option has its pros and cons. Keeping your usual number meant that the folks back home can reach you without making an international call. On the the other hand, you'd have to fork over roaming fees to call home and to reach anyone in Greece.
Getting a local SIM is great for calling within Greece, but you'd still have to pay more to phone anywhere else. Also, remember that once you remove a SIM card from a phone, the number attached to it is essentially useless. If someone tries to contact you, the call goes straight to voice mail and you get no alert that they rang. Similarly, text messages would be lost in space while your SIM card is out of commission. With a dual-SIM phone, however, you don't have to select one or the other. Anyone at home can reach you immediately and cheaply (not vice versa, though) and you can chat with local friends without incurring roaming fees. It's convenient, it saves money, and you don't have to carry around two handsets.
So, does anyone want to share whether they own a dual sim phone and how they use it?