Making use of Explorer pHAT + project kit

yes, you can access 3.3v from pin1,
http://pinout.xyz/pinout/pin1_3v3_power

but as noted there in most cases it's advisable to use a voltage regulator to generate the required supply.

That said, I had a quick look and while not all suitable for the pHAT due to lack of cap touch none of the tutorials on our learning portal use 3.3v supply?

http://learn.pimoroni.com/?tag=explorer-hat

If I was to point you to the best one to get started with I'd say this one is the easiest to implement, though you willl need a few parts (found in the Explorer part kit):

http://learn.pimoroni.com/tutorial/explorer-hat/making-a-minecraft-thermometer