Many "fake" RAID controllers work without any special software as their BIOS masks this, in practice impersonating a dedicated RAID controller CPU, so software alone is probably not going to give you enough hints.
Also, and this is a bit interesting - "fake" (host-based) RAID controllers can easily be much faster than many "true" RAID controllers due to today's CPU speeds being what they are. Of course, the price for this is that you're losing valuable CPU time you could've used for something else - and this is mostly what a "real" RAID controller will fix for you - but be prepared to pay a lot if you want anywhere near decent performance.
There are other things than performance to look for though, like stability, working hot swap, rebuild-speed that doesn't slow everything to a halt, on-line raid level migration and a battery-backed write-cache.
On consumer/enthusiast-oriented motherboards, built-in RAID are common as both types but... The normal host-based stuff like Intel ICH10 and so on are pretty damn fast, depending on the host speed of course - but it's not like it's doing anything you couldn't do with the OS alone (except booting off something more advanced than a mirror).
The cheap "real" RAID controllers on these motherboards are often some truly sad pieces of shit meant for simple and trouble-free mirroring. These mostly perform badly and lack any of the normal features like a decent cache or battery. Stay away from them and never use them for performance-means. They're often weirdly labelled like "SuperDrive" or "EasyRaid" or whatnot and use slow, simple chips for the RAID processing.
As other answers already indicate, a non-fake RAID controller in the context meant does cost a bit - but should be easily identified on this alone. But almost all controllers do at least some host-based processing as well - it's just a matter of how much (or little) and how fast their dedicated CPU/s is/are.