Hi Nan, and welcome. I have a home business, so I sit most of the day in front of my computer. For exercise, I made my goal to get an hour of "extra movement" a day. This can be yard work (my yard's looking a lot better!), walking, yoga, interval workouts, dancing, weight lifting (I do it with bottles of water), going up and down a flight of stairs 10-20 times - anything that gets me moving.
There's a lot available online. Leslie Sansone has some walking in place DVDs and there are some on youtube. I sometimes do it to the youtube video and sometimes just take the moves and do them while I'm watching a half-hour tv show.
I also sometimes do a 10-minute interval workout by Jonathan Roche (also on YouTube).
There's a weekly motivation thread on the forums here that I've found very useful. It starts fresh each Monday. People post their daily goals for the week, then report back about how they're doing. Having to report in about how I'm doing helps motivate me. If I haven't got my 60 min of movement in for the day and it's 10 pm, I'll usually do 20 mins more just so I can put a "Yes" for that goal. People are very supportive there.
Age 61, Height 5'9"
March 2010 145 lbs, Jan 2013 173 lbs
1st Goal 145 lbs 5/25
New goal 140