A few weeks ago I started to set up http://wms.openstreetmap.de to serve aerial images donated by various sources for Openstreetmap use. Currently the system holds data from german communities Lauf an der Pegnitz and Neunkirchen am Sand (thank you very much for donating the data!). It is designed to be extensible with additional data in an easy way. If anybody in the Openstreetmap community is looking for such a service just drop me a line.
The system is powered by Mapservers mapscript written in Python to allow for convenient URLs in JOSM’s WMS plugin. In addition to this I just added support for the Online Openstreetmap Editor Potlatch while learning how to use custom tile-servers with it by chance. This is done by converting tilenames in z/x/y format to the bounding boxes needed for WMS. An Apache mod_rewrite rule provides a virtual tile-URL in the syntax needed by Potlatch and allows for direct edit-links of the available areas now provided on http://wms.openstreetmap.de
The script itself will be released as free software and added to Openstreetmap SVN.
Finally I need to mention that the system is also running on one of the Servers sponsored by german webhosting company STRATO AG.