Syndication time zone problem

I get some traffic to my blog from a regional blog aggregator, but I noticed that my posts would not turn up in their sidebar for many hours after I made them, while some other blogs with which I was familiar would turn up immediately.

I did some checking and discovered that their blog software won’t post any item until the actual time which corresponds to the time listed for that item in its syndication feed. This is to prevent someone from manually setting a time two weeks in the future in order to keep their post at the top of the sidebar.

The time in my blog, as set in my WordPress dashboard, is correct, and if you go to my blog the posts are displayed with their correct times. But when I look at my syndication feed it seems to be UTC, not corrected to my time zone. Can someone tell me what I need to do to my WordPress installation (I assume to my wp-rss2.php file) to fix this?