For those of you who aren't aware, the newest Iridium phone model, the 9575, has automated GPS position reporting (tracking) and an SOS button built in, so if you were planning on investing in a satellite phone anyway, you wouldn't necessarily have to carry two different devices and you would automatically have tracking capabilities via the Iridium network, which is the most comprehensive.
The IsatPhone Pro from Inmarsat allows you to manually send GPS position reports via SMS as well. For a full fledged satellite phone at $599 there isn't a huge price gap between it and some of the tracking devices. Also, by using a prepaid plan with this phone, you can get your monthly cost down to under $17/month. Inmarsat covers the entire world between the 60N and 60S latitudes, which is the majority of the world's landmass, however if you are in Alaska or other extreme latitudes, you'd want to stick with Iridium.
Any of the satellite phone models available provide SMS messaging and SMS-to-email capabilities. The other thing to keep in mind is that there are many different web-based tracking portals available and some are capable of receiving position reports from virtually any type of GPS enabled communications device (including your smartphone), so you shouldn't feel limited by the particular portal that a provider makes available.