Taking inspiration from other Ikea DJ Desks I've seen around here, I decided to use the EXPEDIT bookcase for the base as it provided enough storage space, was a good height and also I already had one! For the tabletop and box I used two of the VIKA AMON tabletops which were the same width as the EXPEDIT and enough depth to fit decks/mixer and speakers on top.
This setup costs about £100 in total, which isn't bad compared to retail versions which will set you back £300+
Step 1: Measuring/Cutting the pieces
The dimensions I used are:
Front = 186mm
Top = 300mm
Back = 254mm
For the side panels I cut up an old Lack cofee table, but you could use anything for this, Ikea make lots of stuff in the same colours. Both were cut to:
265mm x 186mm
Note on cutting
Most Ikea furniture is some sort of laminated wood, eg chipboard core with a nicer look mahogany laminate covering it. I did a lot of reading on the subject of cutting this type of wood without wrecking it. What I settled with was to use masking tape on either side of the cut, leaving a 1mm gap (doesn't have to be 100% accurate). Then I clamped some 2x2 along the line and scored the wood with a sharp knife, then finally took a brand new saw and used the guide to cut as straight as possible. Using this technique I manage to cut each piece without ripping any of the laminate, I'm sure you could do better with a bench saw, just take your time with it.