I've also started some "preliminary" work on photometry.
Managed to pick up a set of Schuler filters from the States ($200) and have already found that the U -series won't work for me. The response of my CCD's is no good below 400A.
One of the better ( best?) books I've found so far is "Astronomical Photometry" by Henden and Kaitchuck. It explains the issues of achieving repeatable magnitude estimates. Although a bit dated in terms of technology, it does a wonderful job of explaining all the variables which can influence the accuracy of the results.
I'm using AstroArt4 and CCDSoft with a 12" LX200 and an ATiK16ic ( the Canon 350D and the Starlight MX7c were no good - colour response etc)
Certainly not for the fainthearted, but interesting fun nevertheless.
There's a very good CCD photometry web article on the BAA variable star site.
http://www.britastro.org/vss/ccd_photometry.htm