I used a fitter I got from Cash and Carry in Sandyford. I've had the kitchen for two years and no problems. I found him very good value and very good at his job. His name is Vincent and as far as I know he's the only one that branch of Cash and Carry use.
I'm planning an IKEA kitchen installation in the next couple of months; would appreciate any pointers/contacts for specific installers that anyone has used (plus any more general advice/pitfalls I need to look out for).