There are several in town that Host PCT hikers. As mentioned above they put their information on the board at the hardware store. Wrightwood is a scheduled stop for most PCT hikers so as to resupply and pickup packages they've mailed to themselves at the Post Office. (BTW, Wrightwood is well spoken of in many of the PCT hiker blogs).
Most of the PCT hikers come through town during the month of May, but some hike the trail in portions and can arrive at any time. That was the case of a PCT hiker from Canada just a few weeks ago. (She was hiking the PCT trail in sections and had gotten snowed out in the Sierras and so took a bus South and began hiking this portion of the trail).
She came down the Acorn Trail and spent the night with a couple here in town who host PCT hikers. They also drove her to the Acton or Aqua Dulce area where she could cache some water.
I was able to give her a ride back up to the top of the Acorn Trail as she was a "purist" and wanted to hike every foot of the trail. She hoped to make it to the southern portion of the Sierras where she began the Sierra portion of her trek, before the snow chased her even further South to start that portion between Mexico and here.