Okay - let me first say that I'm no expert on Lake Anna. But I CAN say that I've taken a few LM's out of there. The best advice I can give you first off is to get a really good map of the lake. A company called GMCO makes a great version and they can usually be purchased at the Bass Pro Shops in Hanover, MD (not too far from Westminster). If you're planning to launch at Lake Anna, I like Anna Point Marina near the 208 bridge (www.annapoint.com). They open at 5:30am and the bait shop carries the maps.
For the fishing, last I heard, LM's were still in the summer pattern, although you can find them moving into the shallows close to docks, riprap and weeds in the early morning and late evening. The primary baitfish are American and Threadfin shad, and blueblack herring. Early morning and late evening, you can get a few nice ones right off of riprap and docks using a popper that imitates those baitfish. My neighbor (and fishing partner) had great success with an Excalibur Pop'N Image in the Threadfin shad pattern. Crankbaits with similar colors should work too. Towards the later part of the day as it heats up, senko's in a dark pattern fished deep seemed to work well.
This weekend, the weather is not supposed to be nearly as hot as it has been - with Saturday being overcast. Hopefully, the bite will begood as I'll be on the Lake as well going for Stripers!
Good luck! - JC