Welcome to TE and to the Mid-Atlantic group!
When you say "slow" - how slow is "slow"? Do you noodle along at 10 mph, or can you maintain upwards of 18-20 mph on the flats? What are your goals for cycling? Do you want to become faster? Stronger? Ride longer rides? Climb better? Ride comfortably with a group?
Also...keep tabs on the Mid-Atlantic forum here at TE. We occasionally do group rides - both on and off-road - that are friendly and geared towards casual good times.
Also...a group of women affiliated with MORE (Mid-Atlantic Offroad Enthusiats) have a series of rides called RLAG (Ride Like a Girl). While primarily off-road, they are in 2008 making a concerted effort to include more road rides in the mix to appeal to the broadest possible group of riders. Rides are all generally beginner friendly and in the VA/DC/MD area. I've been on a few and always have a great time. Contact Liz (see the RLAG link) for more info and to get on her newsletter email list.
If your goals are to get up to the point of doing some hammer-time, I do a Sunday a.m. ride with the Bicycle Place - off Rock Creek Park in Silver Spring. http://www.thebicycleplace.com/ride_with_us/index.html
The ride is "spirited" and a heckufalotta fun (and a great way to meet other cyclists)! The ride is broken into 3 groups - A - the stupid fast guys; B - the stupid fast guys who stop to regroup and catch their breath, and C - the rest of us who want to do an aerobic fast-ish ride (16-18 mph over about 28 miles, which is honestly a whole lot easier to accomplish with a group), but not kill ourselves in the process...oh, and have a fun time doing it. It's a great training opportunity for fitness, and includes pacelines and climbing. Talk to the folks at the shop if you're interested or even PM me for the skinny.
2007 Seven ID8 - Bontrager InForm
2003 Klein Palomino - Terry Firefly (?)
2010 Seven Cafe Racer - Bontrager InForm
2008 Cervelo P2C - Adamo Prologue Saddle