While I assume the USB output voltage will be fine, I am wondering a bit if there could be any issues using my standard little USB with mini USB charger to charge my USA cell phone in Thailand? I don't bring my PC and I typically hit the local Internet café as needed a few times a week. It seems like I could recharge my phone then by plugging in the USB charger. No I don't have a smart phone or anything like that. Just an old flip top phone with voice and text.

Just look at the specs on the USB charger to see if it has universal voltage such as 90-240VAC. If so, not a problem. If it says 110VAC then no you can't but you can easily pick up a USB charger cheap here.

Not knowledgeable about this at all, but logically the charger may be different in the US for 110V, but surely it steps it down to the same voltage when connected to the phone. The OP wants to plug in his USB cable from phone to PC. This will therefore be OK anywhere in the world. US USB ports deliver the same voltage/current as Thai ones.

USB charger: a device plugged in an AC socket?

99%: no problem.

Would be very suprised if chargers exist that are not specified for 100V to 240V AC, 50 Hz to 60 Hz input.

Typical spec (you might need a magnifier ):

Not knowledgeable about this at all, but logically the charger may be different in the US for 110V, but surely it steps it down to the same voltage when connected to the phone. The OP wants to plug in his USB cable from phone to PC. This will therefore be OK anywhere in the world. US USB ports deliver the same voltage/current as Thai ones.

Correct. I just want to plug my phone into the PC USB outlet.