GIS for Telecommunication
I worked as a GIS analyst in the celluar telecommunications industry for a short while.
Most of my tasks centered around working with coverage data, i.e. making coverage maps. I also did a lot of analysis with Census data, determining how many people we covered, what services they were covered with, and how many people lived in areas with "good" coverage. A lot of the coverage modeling software is GIS-enabled as well.
When I was in telecom, most companies were using MapInfo. I'm not sure if this is still true. We made heavy use of the Vertical Mapper (raster analysis) extension do work with coverage data.
Well, I would start by learning MapInfo, if you don't know it already. Training is available here: http://tutorials.mapinfo.com/tutorials/Index.htm. It's hard to come by free telecom data to practice with, though.
There are lots of different areas of Telco. I'd suggest looking into Fiber-to-the-Home (FTTH). If you're in the US, stimulus funding for deploying fiber to rural areas makes this an attractive area. (This sure looks better than LightSquared plan which interferes with GPS reception.)
The relational database designs for modeling fiber connectivity I've seen are quite complex. Keeping track of splices is especially challenging. It makes me wonder if something other than the relational model would be better suited.
From ArcFM's Fiber Manager.
Here's a related question.
I once worked in Telecom project and learned a lot out of it. The best GIS work i have seen in Telecome sector is Telcordia. Have a look on their brochure which explain little bit what they can do in Telcome. http://www.telcordia.com/collateral/brochures/net_engineer.pdf