I made a quick and filthy script[0] to pull out job listings from indeed.co.uk - it's pretty scrappy but maybe someone wants to try and improve it (or generalize it to other countries)
In [348]: %run salary.py "London" "graduate developer"
Job Title: Graduate Developer
Location: London
Salaries:
20000 - 794
40000 - 288
60000 - 85
80000 - 25
100000 - 19
Number of jobs: 1,211
Average salary: £30,057
In [349]: %run salary.py "London" "software developer"
Job Title: Software Developer
Location: London
Salaries:
30000 - 5762
50000 - 3303
70000 - 1298
90000 - 590
110000 - 345
Number of jobs: 11,298
Average salary: £46,018
In [350]: %run salary.py "London" "cobol developer"
Job Title: Cobol Developer
Location: London
Salaries:
50000 - 7
80000 - 4
260000 - 3
Number of jobs: 14
Average salary: £103,571