I do love shooting macros and continue to experiment with this photographic style.  I have found that I can get pseudo-macro results with my 18-200 lens by putting it in manual focus, instead of auto-focus.  For some reason I can get closer to the subject in manual, within 12 inches or less.  On auto-focus I can only get within 18 inches or so, which just doesn't cut it for a macro.  I am sure there is some technical explanation for that but I don't know it!  In this case though I used my Hoya Macro Filters, which I enjoy quite a bit and you can read my review of them here: