Truphone, a London-based mobile VoIP startup, tomorrow is expected to introduce a flat-rate plan (TruUnlimited for Landlines) that would allow its customers unlimited calls to landlines in 38 countries for just over $14 a month. In some countries — the U.S., Canada, China and Hong Kong, for example — the plan would also allow unlimited calls to mobile phones as well. Truphone is also offering another plan (TruUnlimited for Mobiles) that would allow unlimited calls to mobiles and landlines in 64 countries for about $35 a month. With Skype for iPhone (and iPod) likely to be introduced later this week, this seems to be a pre-emptive move by Truphone.

In a previous post, I noted that the iPhone had turbocharged Truphone’s growth. Skype threatens to take some of that sizzle away. Skype’s entry into mobile VoIP will give everyone a heartache. Truphone and Nimbuzz are betting that by being über-communication clients, they can continue to thrive.

If the reaction to my post about Skype’s debut on iPhone is any indication, the world’s largest international voice service is going to become a major player in mobile VoIP pretty quickly. I’m pretty likely to switch to Skype, mostly because my SkypeIn number has a local number — a service Truphone doesn’t offer just yet.

BlackBerry owners in the U.S. will be happy to hear that Truphone is finally releasing Truphone Business, a BlackBerry application enabling business users to make international phone calls from their devices at wireline rates. You download the application. It works in the background. The minute you dial a number that’s international, Truphone intercepts the call and connects it to the international destination via the Truphone network. This doesn’t need Wi-Fi, unlike Truphone on Nokia and iPhone.

Having been an ardent fan of mobile VoIP startups (including Truphone), I am beginning to worry about the company now. We have seen this movie before — low prices, flat-rate pricing and price wars were all strategies used by desperate broadband voice startups that burned through millions of dollars in venture funding. Will history will repeat itself?