> 1. I have some stuff (a bibliography) in a HyperCard format, but I am
> now using Windows. Has someone created something in Squeak that I 
can
> use to port this stack, or at least retrieve the data? [nb: I did a
> google search but was not able to find anything definitive, although
> clearly the relationship between HyperCard and Squeak has been 
discussed
> in the past].

Have a look at BookMorphs.  A good tutorial can be found at
<http://www.penguin-home.telinco.co.uk/Rolodex_Project/>.  My limited
experience with HyperCard places BookMorphs as a good analogue in 
Squeak,
and the above tutorial seems to approach creating a Rolodex in a
way similar to a HyperCard stack.

However, I know of nothing that would automate this process of going 
from
HyperCard to Squeak (or anything else).  If you have access to a Mac, you
could write some script in HyperCard to dump the data out into a file, and
then read it back into Squeak.

If you don't have access to a Mac anymore, perhaps an emulator like
Executor <http://www.ardi.com/executor/products/win_demo.html> or vMac
<http://www.vmac.org/>, both which should be able to run HyperCard with 
no
Problems.

> 2. Is there a CalendarMorph or anything approaching a widget that I
> could use for selecting dates (e.g. as a filter in a mail application).

There is a month calendar view.  Evaluate:

MonthMorph new openInWorld

MonthMorph, I believe, was new in Squeak 2.9a or 3.0.

Hope it helps some,
Aaron