Perhaps ask in the assisted conception section too.
But the brief rundown.
IVF is the process in which your ovaries are stimulated with follicle stimulating hormones to produce larger numbers of mature eggs. These eggs are harvested in a basic day surgery procedure and placed into dishes with the sperm and left to fertilise. The eggs that fertilise are left to develop for a number of days (depending on the clinic and protocol used at the time) and 1 or 2 of the healthiest embies are placed back into the uterus.
ICSI is a similar procedure but the egg is manually fertilised with an individual sperm that is injected into the egg.
IUI can be done on a natural cycle with out the use of stimulation drugs but many use clomid or low dose FSH to get one good egg if their cycles are not completely regular or for better timing etc. The sperm is basically washed and placed directly into the uterus at the time of ovulation and left to it's own devices.
Now this is just a really basic rundown of the procedures. For IVF and ICSI there are different protocols, different drugs are used etc. If you want more specific info have a look at some of the IVF clinic websites, chat to the girls in AC... or I can probably give you some more indepth basics if you want
What is your DP's male factor if you don't mind my asking?