For a bedroom that needs to hold two children most folks choose bunk beds and while this serves the purpose of where the kids will sleep and frees up some floor space, here is another option. I like the way this looks and all the storage it provides plus I also think it is a better solution if the children are still small. They each have their own bed but no one has to climb the ladder or sleep under the top bunk.
By building the corner unit from Ana White it looks like a custom made (I think I would build the corner unit a couple shelves taller for books) bed set and really adds a lot of storage space for toys and such without taking up more floor space.In this picture from Creative Storage Ideas you can see it all together using sterilite storage drawers in the opening under the beds. In the second photo you can see the final version of the diy building plans from Ana White.
Click here for PDf to build corner unit:
http://ana-white.com/2010/05/plans/corner-unit-twin-storage-bed