While there is street parking nearby, PTE recommends parking in the underground parkade at Portage Place. It's secure, patrolled and offers easy, direct access to PTE via Elevator 6 (near the Carlton Street entrance).
It's also one of the most reasonably-priced downtown parking lots - $8 for a weekday evening (compared to upwards of $12-$14 around the Concert Hall).
Parking in the Portage Place Parkade:
Enter off either Vaughan or Carlton Street, then park and pay before coming upstairs. There are 9 payment machines throughout the two levels of the parkade, and you'll pay for parking at these machines in advance by entering your license plate number and payment. Note: the machines accept credit cards only.
You can also pay by phone, using the Secunik, Honk, or Pay By Phone apps.