+1 for Linden's practice sessions. $5 for the practice and you get to run a course 5 to 7 times depending on how many people show up. The people are friendly and very willing to help new shooters. Make sure to bring 100 to 120 rounds, an IDPA course of fire can have up to 21 rounds. You will also need at least 2 mags that can hold 10 rds min, mag holders are nice but not a requirement. Your holster should be an outside the waistband holster but does not need to be a retention holster. You can also run a revolver but then 3 speed loaders are a must, I believe. I have never run a revolver in an IDPA match/practice. Just be warned, this can be addictive.
You can run with smaller mags. The division will be Custom Defensive Pistol (CDP) designed specifically for 1911s, where the mag limit is 8 rounds. IDPA publishes their rules, and you will find the guidance you need in Section 8.2.3 (although there have been some rule changes this year - does anyone know if this division was affected?). You won't need a high-end, high-dollar, fancy-schmancy holster - just one that you find functional. I do recommend a mag holder, though - a very useful component. My BIL makes his own out of old denim, and they work.
The bottom line here is to have some fun while improving your skills. Most clubs will have a "run-what-you-brung" approach, especially for new shooters. Although, you can get purpose-built holsters, mag carriers, belts, pants, shirts, shoes and hats just for competition. Most of us aren't really at that level that we need them, though.
Livingston Gun Club is hosting an introduction to Practical Shooting on April Fool's Day (no foolin!). The class is free and open to the public.
Info on the class and a printable flyer are available at www.livingstongunclub.org
I would make it a point to check out both IDPA and USPSA. Though similar games, they each have their own distinct approach to practical shooting. Both have a division for 1911s, though USPSA will require you to have more mags, as stages can require up to 32 shots, sometimes even more, though not usually. Both games are fun, though I tend to lean towards USPSA, as I like the higher round count and freedom allowed in stage execution. I know plenty of people who shoot both.
Showing up to a match with your gear is perfectly acceptable, assuming you are comfortable drawing from a holster and can handle a firearm safely, but a practice will be a lower stress environment and give you an opportunity to check things out without necessarily needing all of the gear. Just let them know you are new and someone will help you out. One of the greatest things about the shooting sports I find is all the great people I've met.
Like jiw275 said, take a look at uspamichigansection.org, specifically go to http://www.uspsamichigansection.org/...l-matches.html and click on the list of matches. It shows both IDPA, USPSA and Steel Challenge matches in michigan. Go to the website of those clubs and see when they have a practice night and come on out. Perfect time of year to get started, as most clubs come alive around April as the weather gets nice. No club I know requires memberships, neither for the club or IDPA/USPSA to go to a practice. IDPA does require membership after your third match to continue shooting matches.
We have informal IDPA style shoots most Tuesday eves at Multilakes in Commerce twp, no membership needed but the club is open to new members and it's a great way to check it out.
PM or email me for details, club calendar is on our website in the 'Multilaker' magazine.
http://www.multilakes.com
None issue I've participated in IDPA for 2 years before I got a "card". I'm not a member of any of the clubs I've shot matches at either. Being safe is the biggest responsibility IMHO.