See bottom of post for update.
Joie's lace sleeve Joyce top retails for $152 at Nordstrom.
If you want a similar top on a budget, Forever 21 has a great lookalike. This top retails for $24.80, but hurry - it's almost sold out. (Product code is 2071084815, they may be able to look it up at your local store if your size is unavailable or the shirt sells out entirely.)
*Update - 7/8/10* - I believe the Forever 21 shirt is sold out since this post is originally from February, but I just spotted another similar shirt from Guess. This version retails for $69 and you can click on the photo below if you're interested in purchasing.