Looks nothing like the iPhone and shockingly wasn't even a phone.
I believe when people are saying the "looks like the iphone" they're referring to device where the primary input method is the screen, with less emphasis on physical buttons.
The first Windows Mobile phones were just WinMo PDAs with cellular radios in them. So while the iPaq isn't a phone it's the direct predecessor to many of them.
The iPaq is a particularly direct predecessor as you could get a GSM/GPRS sleeve for it.
My first smartphone was a Sony Ericsson P800. Like the iPhone, it had no face buttons. It came with a stylus but the OS was much more finger friendly than many of the phones I used after. Then I "upgraded" to a few HTC phones running Windows Mobile that again were all touch screen.
Even in 2001 there was the "iPaq". ARM processor, etc. Even used a similar name. No 3d chips were widespread yet, lack of white led tech meant the display sucked too much power, compact flash was tiny, had a resistive screen that was somewhat poorly calibrated, etc.