I am a freshly employed software engineer in a young, successful company. I've worked here during both of the previous college summer breaks and that's when I negotiated my current salary. In exchange for experience I was OK with the offered salary although I expected more. Now I think I've gained enough experience to ask for a raise but I thought it would be wise to check out what are the salaries of others in similar position in order to be in a better negotiating position.
How can I find out what salary should I ask for? I guess it's inappropriate to ask colleagues about how much they are making - or is this normal?