Your window frames are looking pretty old from the outside. There are paint chips, dirt and grime and a dull look to the old colour. But it doesn't have to stay this way: You can clean and paint the windows from the outside using a ladder--if you're on the second story--and regular painting equipment. In fact painting outdoors may be easier than painting indoors because you don't need a dust sheet, and the wind naturally ventilates the area.
Check the weather. Depending on how many window frames you have to paint, the job will take you about a weekend, and you don't want to start over because your paint was rained on before it dried.
Set up the ladder below the window and on level ground. If the ladder leans, rest it below the bottom moulding. If you're only painting first-floor windows, you shouldn't need a ladder.
Clean the windows with a household cleaning solution. Get off all the dirt and particulates the outdoors leaves on window frames, focusing especially on the frame. If it's clean, it'll have good adhesion with the primer and paint.
Lightly sand with 60-grit sandpaper any dimples out of the wooden frame to create a flat surface. If there are heavier layers of uneven or loose paint, use a rougher grit, such as 30.
Tape off the glass so that when you do paint, paint doesn't get on the window. Leave a little bit of glass exposed near the frame to ensure the new paint covers the joint between the frame and the glass. Use painter's tape, which is especially made so you can remove it without leaving any residue.
Prime the frame if the new paint you're using is a lighter colour than the old paint. It's a good idea to prime the frame anyway because it improves the adhesion of the new paint to the frame, but it's not necessary.
Paint the frame with latex paint. Latex paint is made to resist bleaching and peeling from exposure to the sun. If you want your windows to retain the ability to open and close, don't paint the frame into the moulding. The paint will take about 24 hours to dry, after which you may need to add another layer, so begin as early in the day as you can. Otherwise remove the painter's tape from the glass, and scrape off any dabs with a paint scraper.