Oh, I did not find any information on the website, too. I got the information through the german APHOG board in a thread about the discontinuation of the prepaid mail-in envelopes. You just have to send them the films with a short letter about what you like to have done to the films and (at least, that's what I did and others as well) the authorization to charge the bill by your bank account. Few days later, you get them back by mail.

Use these addresses for sending in films:

by mail / single films:
Eurocolor Gera GmbH & Co.KG
Postfach 1312
07503 Gera

by parcel service / several films:
Eurocolor Gera GmbH & Co.KG
Heinrich-Hertz-Str. 9
07552 Gera

prices are:

135 development 2,95€
135 framing 3,55 €
120 development 3,95 €
220 development 5,95 €
CD with index from 135 film 3,50 €

+ shipping costs, maximum 2,95€

I forgot what push process costs are, but I can look it up for you.

source: http://www.aphog.de/forum/viewtopic.php?f=79&t=19173

It worked flawless for me so far, just sent in 4 films on Monday. Quality is excellent, imho.