I see a Photoshop add on called Alien Skin which promises great things for upsizing pictures. It has a month free trial. Has anyone tried it.

www.alienskin.com

Thank you for these informations, I did not know these tools, I had a look and...

I did a test with both tools, using their examples, trying to get the best with photoshop only, and the results I got handly were better to me than theirs, except for some jagged edges hard to deal with by upsizing, taking in consideration the base imaghe I used is surely more compressed than the base they used.
They are calling "crisp" over-accentuation, and a lot of details are lost if you look at the examples.

If you want to get something like an impressionist painting, with some more noise on it (particulary with Photozoom pro), I think they are good tools.

It seems to be (to me) that the algorithms are mixed with some vectorization techniques. It can do a good job with rasterized vectors, as seen here : http://www.alienskin.com/blowup/filters/logo.html
But this is a very limitated usage.
I think often, edges have to keep their smoothness rather than being transformed in hard contrast lines, as we can see here : http://www.benvista.com/main/skin1/images/content/ourproducts/photozoompro/pzp2_example3.htm
where the shaddows become so hard.

And US $199.00 for Alien Skin BlowUp, �150.00 for Photo zoom, I think it's worth to upgrade (for canonists) to the new 50D with 15Mpixels instead

Well, just my mind.

Here is to illustrate :

Based on this sample :
http://www.alienskin.com/blowup/filters/apple.html

Most sites will reject upsized images... only accepts native camera resolution picures.
Patrick H.

You don't know Alamy then, where you have to... 

save your money, IMO the difference between any of them and bicubic smoother isn't worthspending the money on.

instead go to

http://www.phototechniqueswiki.com/Article.aspx?articleID=35

get the resize script, follow instructions to create it, create an action in photoshop that calls it.

then for each batch, open bridge, select all, -> image processor, run action

took a few minutes to resize 60 images to exactly 48mb regardless of orientation, crops etc. 

Phil