You can use a bunch of different loaders to do this. Popular ones include Gecko OS (also includes stuff like cheats and some more advanced configuration options like video modes), TinyLoad (has the benefit of being extremely small [<4KB if I recall correctly], and no GUI to boots the inserted game instantly instead of loading a GUI first) and Riivolution (which has some fairly advanced file replacement features allowing modding games quite heavily, but it can also just simply load an out of region game).
I'd advise trying TinyLoad first as it is the simplest (insert disc, open HBC, run TinyLoad), and if it doesn't seem to work, try one of the others.