Id like to write my own tool in Python and then upload it/use it with my ArcGIS Online map. Is this Python-online integration possible?
As far as I know it is not possible (yet?) to publish your geoprocessing service to ArcGIS Online. You can upload and share it through ArcGIS Online or the new ArcScripts 2.0 (Search ArcScripts (BETA) ), but executing it online is not possible. See also: Publishing Geoprocessing Service to ArcGIS online? - Geographic Information Systems Stack Exchange
