So I actually reviewed a few as promised, or tried to at least.  I may
look for more again later but in case I don't here's what I came
across.

All prices in USD.  tried printing same 4 photos in 2 different sizes
at each.

With most you have to specify opt-out for receiving offers from them
and/or them sharing your info with partners.  

Terms and conditions typically excessive with each and with some you
may lose some of your copyrights to your images mostly as a disclaimer
should they get out, etc. but they attempt to preserve your privacy.
I guess even if they don't specify this it's a possibility.  Naturally
I'll sue if I find photos of my family distributed by them for any
purpose.

colormailer [1]

pros

resolution guide [2] to let me know what would be reasonable based on
the jpegs I send them.

measurements in metric - even though being American I'm disadvantaged
in this area I try to overcome my country's shortcomings which they
graciously recognized after entering my address and afterwards
displaced photo sizes in inches  

mention my email alias [email protected] and get 10 free 4x6" prints, and
I get 2 8 x 10"  Henrik who provided this link said he hasn't tried
them yet or I would say give his email address instead as he deserves
the credit for the referral.

International, doesn't matter where you reside.

Clarity, the prints came out very well better than local shop.

In short I recommend them of those sampled.

cons

jpeg filename, should also recognize jpg

more expensive $0.40 for 4"x6" (actually said 4.5)

javascript and popups - eugh a real turn off unless used sparingly and
reasonably (pretty rare) gets a bit confusing and have to tab between
them myself (perhaps behavior better with other browsers).  This may
make scripting more difficult.  

photoworks [3]

pros

cheaper

Web based file upload  

cons

seems to repeatedly time out creating account and logging in

I note it's IIS and aspx (asp + active X? I forget) and I'm not an IE
user.  Person who recommended this site browses the web as MS intended
so might have been smoother for them.

Couldn't log in after N attempts timing out - CYA  

Since I don't live in Canada (yet although US is scaring me lately,
note brushing up on metric) I had to go Googling [4] for others to
compare.  I'll check the Canadian ones listed and see if they are
prejudice against US customers.

photoaccess [5]

pros

First listed (besides the two "sponsored links") so must be heavily
linked to, probably from all their online galleries and related
commercial endeavors for professional photographers selling prints
through them.

Hmm they have some concept of what I want - for my mom to be able to
order photos online but would require I keep my photos on their site
[6] which isn't what I want.

I could make wall calendar, mouse pads, mugs etc from my photos.  I'm
sure there are a number of places that do that.  

cons