Whatever you do don't go to tour operators for this place. We got on the K6 Bus from the local bus station near the main mosque in town. Bus fare is 3RM, its a 45 minute journey. Entrance fee is ridiculously cheap at 3RM per person. There's two of us so the whole trip cost us 18RM combined, tour operators charge between 35RM- 80RM per person.
Its such a simple journey, it'd be silly to waste your money. Bus time are 7.15am and 1pm, get to the bus station a little earlier as buses tend to run ON TIME- we got it right on our third try.
Organisers at Semenggoh are very genuine and care about the Orang Utangs a lot. They are very honest, when we got there they told us there might be a chance that we might not get to see the Orangutangs as they will only come out of the forest if they are hungry. On our trip we saw 6, there are 20 in the forest in total. What a wonderful experience.