These are also called freeze or core plugs. Their replacement is covered on p. 9-55 here: http://oskin.ru/pub/chrysler-dodge/...ynasty_LeBaron_Shadow_FifthAvenue/92FWD_9.PDF
The service is best done on a lift as it is easiest from underneath and you need a good, comfortable (standing) position to access most of them. Sometimes outside engine components and brackets have to be removed. A couple of core plugs at the rear of the engine may also require the transaxle and flexplate to be removed to access them. Some engines and bodies are easier than others.
Review your situation and see if it is something that you will want to tackle. A hammer, drift and socket are the basic tools that you will need. The plugs have to be hit straight into the hole. They won't hold if cocked. If it looks too difficult to do, call around for estimates.
Follow the service with a thorough flush and fresh coolant refill.