I haven't personally known of anyone who has used IUI (Intrauterine Insemination) but I do have some online friends who have used it. I was unsure about the whole procedure, so I thought that I would take a look around and see what I could find to help explain it to me. I found the following page that was very helpful in answering all of my questions along with questions that I wouldn't have even thought of. The last time it was revised was in March of 2002, but I think that it covers most of the bases.

IUI FAQ from FertilityPlus, Information for Patients, Written by Patients.

Here is their description of what an IUI is:

An IUI --intrauterine insemination -- is performed by threading a very thin flexible catheter through the cervix and injecting washed sperm directly into the uterus. The whole process doesn't take very long - it usually only requires the insertion of a speculum and then the catheter, a process that maybe takes a couple of minutes (60 - 90) seconds to introduce the catheter, then sperm injection, and another 60 seconds or so to remove the catheter - going slowly helps reduce discomfort). Sometimes when the cervix is hard to reach a tenaculum is used to hold the cervix, which makes the process a bit more uncomfortable.

Here is what they say it feels like:

Most women consider IUI to be fairly painless -- along the same lines as having a pap smear. There can be some cramping afterward, but often what is felt is ovulation-related rather than from the IUI. The catheter usually doesn't feel like much since the cervix is already slightly open for ovulation -- a poorly timed IUI might cause more discomfort at the cervix.

The site also offers many more types of treatments to learn about.