Be sure to bring along a jacket if you are going on any long bus rides. At night with the AC running full blast it can get uncomfortably cold especially in the mountains.
The fare from Manila to Samar on South Bound was 950 pesos which I think included the ferry crossing from Luzon to Samar. Somehow I lost the tickets and had to pay 90 pesos extra.
It is best to leave from Pasay in Manila because most of the south bound buses leave from this part of town.
Victory Liner is just across the street from PP Liner, South Bound and several others. Pasay is near the airport and traffic crawls most of the time during the day.
Buses leave day and night to Leyte and Samar. You can travel all the way to Davao in Mindanao by bus if you transfer to another liner when you get to Tacloban. Basically you are only limited by your endurance and how much crap you can take.
Vendors jump on the bus as soon as you stop and block the aisles making it hard to get on and off but it's their job.
These buses stop at their company restaraunts along the way every 3 or 4 hours giving you a chance to stretch and use the toilets. The food isn't too bad and they have instant noodles and hot drinks you can take on the bus.
There are ferrys that the buses drive onto to get from island to island. The weather was quite rough when we arrived at the crossing from Luzon to Samar. The ferry was rising and falling with the waves making it very difficult to board or get off.
The drivers would time it so they would get half way on and stop and wait for the next flat spell when they would then gun it and come flying onboard.
One of the trucks fell off and got damaged when they tried to offload but was out of sync with the waves. The port decided to suspended crossings till morning.
The trip took about a day and a half because we lost a lot of time waiting for the weather to subside so we could get across.
The ferry still shuddered every time we hit the oncoming waves and it didn't seem all that safe on that junky old boat but they just turn up the volume on the karaoke machine and no one seemed to notice.
If you are not in a hurry and don't forget to bring a jacket the bus can be tolerable but not very comfortable.
Philippines
update: Ultrabus charged 809 pesos when I made the trip last week (sept 2007)
The fares seem to vary greatly up to 1300 peso for no apparent reason. All include the ferry crossing ticket between Luzon and Samar.