if you own (or can borrow) some spring compressors and a socket set + a jack and jackstands obviously, pretty easy.
Even without spring compressors it's not too hard.
If your not confident doing it yourself (which, i'm guessing is why this post is here) get someone who's done it before to help you - it really is very easy though.
*jack up car, remove front wheel.
*unbolt brake line from strut (can leave it connected to caliper)
*loosen nut at top of strut (under rubber cover thing)
*remove strut to hub bolts
*remove strut to body nuts
take strut out of car, then
*fit spring compressors to spring, tighten so spring is clear of top hat
*remove top nut that we loosened earlier
*remove top hat
*remove spring
reverse procedure with new spring.
rear is the same except there's only one bolt at the bottom, and there's no brake line attatched to the strut.
Edit: just thought i should check vfaq and it did indeed have what I needed,
click here for relevant vfaq.com page
You only need to worry about the first 4 pictures and corresponding info, as the rest is to do with fitting new shock inserts, which your not doing.