Along with the photo Siwon tweetd above, he promotes his 'brother' showcase:

"Brian Joo Mini Showcase Live in Malaysia" July 10, 2010 (Sat) !! http://twitpic.com/1v7vlt

and followed by this tweet:

And For more information go to www.rhythm-land.com or www.facebook.com/rhythmland! Yay :D!! http://twitpic.com/1v7vz5

All tweeted in english :) I guess its easier for fans to understand with english.
After half an hour, Brian, who saw his tweet replied him saying:

@siwon407 thank u little bro... 역시 이래서 형제가 좋은거야... 최시원 화이팅
( @ siwon407 thank you little bro... as expected, its the good going bro, choi siwon hwaiting!)

Its good seeing both of them so close and Siwon promoting Brian's showcase to his fans~ Guys, pls support Brian at his showcase or pass the message around!

Credit: translated by Ting18♥ @ DKP
Source: Siwon and Brian's twitter.