Can I do this in iCal - new user

Hello all you users of ical,

Would one of you kind people please be able to tell me whether the following is possible in ical?

I am a freelance technician and book jobs with different companies from three days up to six months. The people who do the boookings are very busy and have to juggle a lot of people and dates. I would like to be able to mark very simply on a calendar (picture the month view) which days I am booked and which days I am available, and then allow these companies access to it so they can see at a glance when I am available. I'd like to strike through or colour the days; - blue for available - red for booked.

I'm on a mac and so are most if not all of the people I want to communicate this to. I have messed around with ical a little this evening but don't seem to be able to get the desired effect. I think it's obvious that the sharing part of this possible, but can I mark of the days in the way I described?

Many thanks,

Philip