There are plenty of reverse phone look-up services that will reveal what type of provider and the name of the carrier for landlines and cell phones. My favorites for these are www.phonelookup.com and www.phonevalidator.com. But what if you need to know the provider for a “toll-free” number, so you can obtain subpoena data? Well I have seen these types of sites come and go pretty regularly, but my current favorite is www.customtollfree.com.
I have seen a whole lot of people in my profession ask the same question over and over again. Is it legal to record a phone call or personal conversation? And if so, does it require one party consent or all? Here is a good reference to answer that question “Can we tape?”. I suggest using this site only for a general guide and always consult your local laws before conducting any surreptitious recordings.