The 2011 refresh if any, will be minor adjustments as the 2011 Early models just came out.
MBPs won't see a proper upgrade until early 2012
I hate when people give advice while stating opinion as fact. The truth is nobody know when the update will be or how big the update will be.
The refresh history suggests a refresh could occur around the Sept-Oct timeframe, but if you notice Apple seems to be lengthening the time between refreshes. The last two mbp updates were 100 days longer than the avg, which would place the update into early January. But in April there was a rumor that the next mbp refresh would be a new case design that wouldn't occur till 2012. The next MBP may wait till they can use the ivy bridge chip which is rumored to not be added to Macs untill April of 2012. Although the most recent rumor says that the redesigned mbp's are expected to be released before Christmas. So in summary of these rumors, the next mbp's could be released anytime from Sept 2011 - April 2012 (an 8 month period...)
You will get lots of opinions from both sides here at MR and I agree with them both. In one side we have....
"Go ahead and buy now. There will always be something bigger and better coming out and you can wait forever. Don't wait because of rumors because it might not come true, it might be longer than you think, you might not even like the new design, you may start to hear rumors of the NEXT update and how awesome that one will be. Imagine how much time you will have wasted on a PC that you aren't happy with when you could actually be enjoying your computer!"
Then on the other side...
"If you can wait do it. The current model has been out for 6 months and according to the buyers guide is expected to have a new model within 2 months. The next model is supposed to be a major update, possibly being thinner, lighter, faster and better battery life! You will have buyers remorse if you buy new and less than 2 months later a super awesome upgrade comes out. Technology moves so quickly that it is always best practice to get things as new and current as possible."
The reality is both are good arguments. Only YOU can decide how badly you want it now.