I covered my entire garage with Hardie plank. It is a good product that is a bit of work to install. But once you install it, it should last forever, provided you paint it every 8 to 10 years.
My garage was first covered entirely in OSB, then tyvek. If you use foam board or something soft, the hardie install will be more difficults because if you miss a stud, the nail will probably blow thru the hardie plank.
I installed 450 (12 ft pieces) of hardie plank. I did buy the following tools:
Malco hanger tool ($20)
http://www.amazon.com/dp/B00009YUMG/?tag=atomicindus08-20
Pacific International shear SS404 ($250)
http://www.amazon.com/dp/B0000DCBJH/?tag=atomicindus08-20
I would not do this job without the hanger tool. Once you get your first row level, the row above will always be level. I went 20 ft up my walls, checked the level every few rows and never had to correct for any level problem. The hanger tools work very well.
The shear tool is a must also. It allows you to cut the hardiplank without creating dust. You will need to rip a board (with a cicrular saw) when you reach the top, but most of your cuts are to only to set the length of the board. As others said, the dust is toxic (i.e. DEADLY), so do not breath it in. What happens is silica dust gets in you lungs and never leave, so a little dust is a very bad thing. If you have to saw hardiplank, wear a good dust mask and use a fan to blow the dust away from you as you cut.
I use a roofing nail gun to attach it. Used long nails to reach the studs. You can screw it or nail it, just read the "well written" install instruction on the James Hardie web page.
Is the job doable, yes, but it is alot of work. I had my wife as a helper. You will need a helper to help handle the long 12 ft pieces, they are flimsy, but I only broke two piece due to miss handling. At $5 a piece, do not worry if you break a few.
Goodluck...