If you want something convenient and mostly working currently the best option is Yappari.

Telegram can work with Pidgin http://talk.maemo.org/showthread.php?t=94324 but will crash when you receive a message. Restarting Pidgin will result in showing the message, so it kinda works. It is also missing some Telegram features and history.

You can also use https://web.telegram.org it works on iceweasel with easy debian but is very slow. Has the standard Telegram features and albeit slow it works.

Problem with any of the Telegram options is that there is no solid push method to receive messages. Would be nice to see someone working on it again.