please write a tutorial for it!

OK – will add that to the todo list. There is some documentation online here plus plenty of examples that come with it. Perhaps the most useful example is this one Lorenzo added – shows how to build an event calendar with it.

Does it support Hijri(Lunar based),Jalali(Sun based) and Hebrew Calendars.

Well not right now but in theory it could. The calendars would need to have some quantity which can be equated to the calendar “units” of year, month, week, day, hour, minute and second. All the real math happens in the engine classes, even determining (what are normally absolute) values such as the number of days in a week. So (in theory) all you need to do is perform the required calendar math while implementing this interface. I say in theory because it hasn’t been done yet, other than the two existing engines, one using Unix timestamp-based calculations and the other using PEAR::Date. My guess is the notion of a week may be problematic is some cases but that can be fixed.

Also How well does PHP support I18N? Does it support BiDi?

Not so well. For basic i18n you can change locales as with this example. Dealing with stuff like character sets and unicode is not natively handled – you have to start messing with stuff like the mbstring extension.

(Update) You may also be interested in this http://pecl.php.net/package/fribidi…

Things may be getting better soon – an reads on the subject; http://www.zend.com/lists/php-dev/200303/msg00656.html. Otherwise best to check in at the php.i18n mailing list http://news.php.net/group.php?group=php.i18n.

Those aforementioned Calendars are usually done right -to-left.

That part shouldn’t be too much of a problem. PEAR::Calendar doesn’t itself generate any output – just generates a the elements of the calendar as a data structure for you to loop over and render whatever you want. Would probably just be a case of concatenating a string.

Maybe build memcached support or at least some sort of caching hooks so the user can implement there caching method of choice

Perhaps some hooks is the best way – do with the objects as you like (and saves me having to reimplement stuff done elsewhere). Thanks – reckon I’ll do that.