I really suggest the EQ2 Map interface, it has helped me a ton when I first started a few months ago.
http://maps.eq2interface.com/
I don't think it changes the actual interface of your UI, it just adds points of interest (POI's) on your maps (such as quest locations, named enemies, etc.) and it adds alot of maps for dungeons and instances that EQ2 wouldn't normally have. Some of the newer dungeons and instances still don't have maps yet.
As for your coordinate question, both posts above should work. One easy way to do it is to use ctrl + c to copy a coordinate location from a webpage, then use ctrl + v to past it into that little bar below your map and click on the little yellow circle thingy next to your map coordinates to make a path to it and mark it on your map.
Just a little clarification of the map window coordinate entry. You can use the + sign in front of numbers, you can use decimals, and you can have a space after the comma if you want. It's very flexible, just so long as you have 3 numbers separated by commas. All of the following will work in the map window:
123,-45,678
+123,-45,+678
123, -45, 678
123.56,-45.67,678.90
The only time you may need to modify a coodinate is if the poster only provides 2 numbers such as 123,678; then you need add the middle number. Zero normally works fine so long as you aren't in a multiple level area (the middle coordinate is the height coordinate, so you would enter 123,0,678). Zero will still work if you are in a buidling or dungeon, you just won't know which floor it is on.
On a side note, you are probably better off using the /waypoint 123,-45,678 if you are in an area with no map.