Google announced that they're rolling out "broad match modifier" AdWords targeting feature to more countries this summer, which's currently availble in UK and Canada.
"We've heard developers asking when this'll be supported in the API, so we want to let you know that it already is. To use the broad match modifier, simply add plus signs (+) to your keyword text as desired. Because these keywords are still considered BROAD match, no additions to KeywordMatchType enum are necessary.
Unless you prohibit the entry of the plus symbol (+) character in keyword text fields or reports, you may not need to change your code at all. However, we recommend testing to make sure," explains Google.