There are many map projections that leave the Pacific Ocean intact as one piece, you simply need to reproject your data.
In ArcCatalog is easiest... use the toolbox and select Data Management Tools >> Transformations and Projections >> Feature >> Project. Select >> Projected Coordinate Systems >> World; now select your desired projection...
Here are a couple of projections that are "Pacific-centric" (in a manner of speaking) and which you choose depends on your purpose:
You can learn about others here http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?TopicName=List_of_supported_map_projections