Hydrofoil to HCMC
Take the Hydrofoil between HCMC and Vung Tau. In 2003, it costs about US$10 (120,000 VND) for a round trip, but as of 2011, the rates are now 200,000 Dong; the trip only takes one hour and 15 minutes. There are about 6 hydrofoils each day. In Vung Tau, they pick up at the pier on the southern end of front beach.

There are two companies operating the hydros: Vina Express and Greenlines. I think their rates are exactly the same (as they should be in a communist country!) and they probably even use the same boats. The hydrofoils have seating for about 120 people--during my trip, maybe 1/4 of the seats were full. There were some locals on board, I think they get a big discount on the fare.

Here's a schedule from the Vina Express website:

HCMC to VT departures
0600, 0830, 1030, 1230, 1430, 1630

VT to HCMC departures
0600, 0830, 1030, 1230, 1430, 1630

Ticketing Booth-Vung Tau
126 Ha Long Str. Vung Tau City

According to Google Maps, the address of the hydrofoil terminal is:
Express Ship Harbour‎
120, Phường 2, Vung Tau
Ba Ria - Vung Tau, Vietnam
(064) 385 6069

The terminal is located near the end of the peninsula, on the opposite side from the beaches. The terminal is on the east side of the peninsula, the big beaches are on the west side.