Has anyone successfully used the mkgmap program to convert Open Street Map files to Garmin .img files?

I’ve given it a go with a download of the British Isle but the program has been thrashing the harddrive to over 2 hours (quad core i5 with 12Gb ram, so not too shody) without any sign of finishing.

I’m beginning to wonder whether I’m caught in some sort of infinite loop!

I’ve used Mkgmap a few times, I have created a few maps with it. I would suggest starting with a smaller area to try it out. ie just a single county or city.
Try the Geofabrik downloads: http://download.geofabrik.de/europe/great-britain.html
Or these Metro extracts: http://metro.teczno.com/

Also, its a good idea to split the OSM file into smaller tiles, before using Mkgmap. ie first use splitter.jar to split the map into tiles (I think its default options should be OK for this). Then use these tiles as input for Mkgmap, to create your maps in Garmin format.