I came across this word in a received SMS

Gonderirken. I have not see this ken suffix before but I think it means when
Am I correct and can iken also be used for when
can anyone provide some examples of how to use this suffix or point me in the right direction of where I can learn more about this

Thanks in advance for the assistance

Yes, -ken is more like "while" in English.

x -ken y oldu. Both x and y happen at the same time. Often x starts first, but not always.

Ben kitap okurken annem arkadaşıyla konuşuyordu.
My mum was talking with her friend while I read a book.

The famous song:
Üsküdar'a gider iken aldı da bir yağmur
While I was going to Üsküdar it started to rain

İm studing it so here is  just updating on the link

http://web.archive.org/web/20080214113704/www.turkishlanguage.co.uk/iken.htm

For the suffixes you dont know;

http://www.dnathan.com/language/turkish/tsd/

 Thank you Umut Umut