To make a decent build we need more informations.
If you want to play OC then just start as cleric to lvl 4 and then either give only one monk lvl or 4 as well, then continue in cleric as cleric gives you more than monk. The third class could be fighter or champion of torm (possible later and only if you take weapon focus on melee weapon, unarmed doesnt count). If fighter this would be probably the best level spit:
1: Cleric
2: Figher
3: Cleric
4: Fighter
5: Cleric
6: Fighter
7: Cleric <- 6BAB = 2attacks
8: Monk
9-X: Cleric and 1 level of fighter anytime later
This is viable for OC/SoU/any SP module where max lvl is <=20
Also you have to decide if you will be strenght based, dexterity and weapon finesse based or wisdom and zen archery based. Str means lower ac but better damage, dexterity means good ac but bad damage and wisdom means ability to attack from distance, good ac and good stunning fist DC if your enemy comes too close and you switch to unarmed.
If you need build for higher levels then try this:
http://www.gustaver.se/nwn/ 
