I have the garmin and heart rate strap. I wear it under my sports bra like the others have said. However, some of my sports bras have elastic that is too tight and it makes me feel like I cant breathe. So when I wear it, I have to double check what I'm wearing it with!
Also, I now have to put duct tape on my chest underneath the monitor piece. I went for a wedding dress fitting a few months ago and the lady though I was self-mutilating...having the strap under my sports bra causes the monitor piece to cut my chest on a daily basis and keep re-cutting and scarring it in a rectangular shape....I'm not sure how, since it is facing outward, and I have no excess skin for it to catch on (my upper body looks like a 12 year old boys).
That polar sports bra may be a good idea for those of us that can't seem to get it together with the strap.