RE: How do you know what you like unless you buy it?
You can check out www.thebabywearer.com to see if there is anyone near you who either gives sling lesson or workshops, or just has a collection - you'd be surprised where you find people!
Or you could pick one or a few candidates and either buy them gently used on a swap board (either at yahoo groups or babywearer) or buy them new and resell anything you don't decide to keep.
The easiest thing to start with is a pouch, but you need to get an exact fit which is difficult when you're pregnant. You might want to try the Kangaroo Korner Adjustable Cotton Pouch, which has some flexibility since it is adjustable. Most people rave about the fleece pouch, but if you're due in July that probably won't work for you. :) Tanya at KK is very helpful, you can email her for sizing advice.
You also might want to try a stretchy wrap - newborns really like those. They do have a bit of a learning curve but are very easy when you get the hang of it. The best one is the hug a bub but it is $$, there are several that are not as expensive, including the Moby wrap, I'm not sure what else.
HTH!
Nancy, mom to
DD1 5/04 and DD2 3/07