the software itself (pro tools) is not that amazing, it's the HARDWARE of pro tools that makes it what it is.
there is the REAL pro tools, with a PRO MIX 24 card EXPENSIVE
there is the LE version of pro tools, with the DIGI 001 rack, it is quite cheap (1000 USD)
there is a FREE version of pro tools LE, on
http://www.digidesign.com, but again, without th ehardware its not that much better than other multitrack audio recorder with midi sequencing features.
equivalents? Steinberg NUENDO maybe.. same thing, you can have the hardware+sopftware version or simply the software version.
Creamware LUNA II maybe? mmhh
good luck