I want to train high intensity interval in running and would like to buy a pulsometer that can export later pulse recording to the computer (preferably in mac os x), do you know any?
The pulsmeter market is very big with a few global brands (Polar, Garmin, Suunto) and lots of local brands. I have been using Suunto for 5 years now, both a "R to R" recording belt and a watch for feeback during the actual practise.
If you are about to buy one, here are some simple checks regarding service and maintenace:
Regarding features, the "go to" site is DC rainmaker, see DC R blog.
I would check out the Polar line of Heart Rate monitors. They have been in the business for longer than most. There are several higher end models with computer interfaces that can download data.
Failing that, many of the new running watches that have GPS allow computer connections to download and some of them now come with HRM straps, so I imagine it should be possible. (Like the Garmin Forerunner series).
There is some really cool watch technology out there!