I didn't use any worksheets in case anyone likes that kind of thing in class. My idea was fairly basic. You're welcome to obviously change anything you want or make additions.
 
1. In the class beforehand I gave my students homework to find any English text message and chat abbreviations - suggested the Internet to search. I gave a couple examples after explaining what I'd meant like l8r = later; cya = see ya; c u = see you, just to see if they understood.
 
The following class I asked if they'd done homework, as I normally do and check it. Then continued with the PowerPoint slides. After asking them what 'abbreviation' meant and showing examples again, I asked students to come to the board and write 2 or 3 of their own homework abbreviations and meanings on the board to compile a class list. Then in my PowerPoint I showed my examples and I made sure my kids wrote down my abbreviations that they didn't have already. Afterwards, I explained to them that I wanted them to use their notebooks to write out small chat messages back and forth as if they were text messaging or chatting with their friend. It was tough to explain so I re-explained in their pairs for students who misunderstood and even tried to show them with their notebooks, gesturing, etc.
After giving them time to write out their messages I had them present with their partners in front of the class.
 
Below is the link I had with a crapload of different abbreviations.
 
http://www.webopedia.com/quick_ref/textmessageabbreviations.asp
 
Hope the PowerPoint and lesson work out. Have fun!

This lesson worked really well for my students! They had a lot of fun with it. I also taught them about smiley icons because some are different in Korea.

http://www.webopedia.com/quick_ref/textmessageabbreviations_02.asp

now this is a modern and relative lesson plan that can be used in everyday activity

This worked well to keep my high school students (all 3 grades) interested! Thanks for the idea :) They didn't speak much English during the process but afterwards in the hallways they started saying "see you"  & "see you later" while giggling profusely.

I recently did a class with my Grade 2 high school students on technology, the Internet, text chat and emoticons. I pulled various bits from other posts on the page, and some other online teaching materials.

It was very well received!! I got the students talking at every opportunity, and it turned out to be a very productive class!

I refined the PPT and worksheet after the whole week of classes, as some bits needed tweeking, so I think it's all good now. This took up the whole 50 min lesson, and there is the option to set the last activity as homework if you wanted.

You will need an internet connection for the middle part of the lesson (slideshow talking about websites people use)

I have put my notes from conducting the class on to the PPT slides, so have a read of them first.

I hope you like it!

PS. If you use this on lower level classes, it may be useful to have your co-teacher explain the vocabulary on the first reading activity, just so there is no confusion.

I also did a text lingo lesson last semester that went over pretty well with my first grade HS girls. I started by eliciting text speak words in Korean, and asked throughout the lesson if equivalent terms existed in Korean for the words we were learning. My Prezi link is: http://prezi.com/_7hpaxokum2q/lp6-text-speak/?kw=view-_7hpaxokum2q&rc=ref-17081880
Materials attached!

I am addicted to Prezi, haha. Thanks for sharing!

This topic was a lot more effective than I could ever hope for, so thank you everyone who contributed. I took some bit and pieces from the materials here, added my own, and now I will share what I came up with. For the quiz I made at the end, you should play around with it and look at the animation pane to see how it works, otherwise just post any questions here.