I was able to find a metered parking spot when I stopped by for lunch, be sure to bring change with you. I think there was also a parking lot but I spotted a street space before I found the lot. Most of the parking in the shopping/restaurant district is metered and limited to 2 hours.
I also noticed that addresses don't run like they do in Chicago, where 1500 is across the street from 1501. I missed Houston's the 1st time I drove by because the address was 1550 and across the street was 2171. So I think you can only go by the numbers on the odd or even side. It's helpful to have directions from Mapquest or at the very least the nearest cross street.
Getting to Manhattan Beach by car is the most convenient mode of travel in my opinion. Your own car, a rented car or even a hired Limo.
Los Angeles International Airport is just a few miles up the road from Manhattan Beach and at the airport there are lots of car rental companies that will service your needs.
On-street and public parking is limited in Manhattan Beach, especially in the summer months, and even more so on holiday weekends. There are a few metered, public lots around downtown MB, as well as an underground parking structure smack-dab in the middle of downtown (under the Shade Hotel and the MetLox shopping center). If you are lucky enough to find a parking spot, be sure to feed your meter, adhere to the time limits (most meters are 2 hours max), and curb your wheels if you park on a hill. The parking attendants in MB are very good at their jobs and generously hand out parking tickets.
If you are going with a bunch of people, I highly suggest leaving all cars but one at the Target store in Manhattan Beach or something. There is one off the Rosecrans Exit. When you get down Manhattan Blvd near the ocean, all stores start having signs warning non-store parkers. As you go down Manhattan Blvd. and see the ocean and the pier, try and find a parking spot to your left or right, because once you start hitting traffic lights, parking becomes metered. Park on Manhattan Blvd. or any of the residential cross streets up there, and walk down, it only takes a few minutes to walk down and it is WAY worth the free park. Plus, it is impossible to find any parking meters that last for more than 2 hours. There are some that are 5 hour meters, but I would highly doubt you would be able to get one - and you have to PAY. No good!