Unlike product / application development projects, packaged ERP implementations are quite different as we are primarily trying to map the package to the existing business process. Although, there might be a need to create new RICE components (Reports, Interfaces, Conversions and Extensions) which will need additional coding.
Oracle follows and advises their clients to use Applications Implementation Methodology (AIM). However many implementation organizations tend to follow their own methodoloies, which are similar to AIM at a top level but when it comes to actual granular detail they differ a lot. Especially the documenting part differs widely from organisation to organisation. Sometimes, even user organizations have their own implementation methodologies. So, things become interesting and at times frustrating when actually one sits down to do a comparative analysis of the various implementation methodologies and finalise upon the deliverables at different stages.
There are quite a few good blogs on AIM in Richard Byrom's website. One can also download AIM software from the following link below, but do ensure that you do not run it on IE6.0. This however runs fine on Firefox: