The Gimp is an open source photo editor. It is a free advanced alternative to Photoshop and has several advanced functions such as layers, healing tool etc. Some of it limits is that it cannot edit in 16 bits, but the program develops fast and the disadvantage might soon be history.

This is poor mans photoshop but there is probably not anything you can do in photoshop that is possible to do in Gimp.

I have now used the GIMP for a while and now i got used to its somewhat cumbersome interface. It is not reaching Photoshops CS standard, but easily stand up to Photoshop Elements. Since its really low price 0 dollar means that you can spend your money on expensive photoequipment instead.

Gimp is now easier to use and the increasing use indicate that more people appreciate the program. It may not have all the automated features as Photoshop, but there are plenty of happy users who like to advise you how to make different effects. Gimp requires a little curiosity and exploration. Looking for a program of automatic functions keep looking since Gimp means understanding and hard work. The flexibility and the potential is probably what I love most of the Gimp.

 I thought I collect links to useful resources in this post.  If you know a missing link please tell me in the comments.

Updated at 2010-02-04

Introductions

Introductionthread for Gimp at Gimptalk – very thorough introduction thread that will guide you through the initial step.
Introduction to Gimp
Jiscmedia about Gimp

Manuals and books about Gimp

Usermanual of GIMP
Grokking the Gimp (Book about GIMP)

Resources

Videos about Gimp

Restore old photos – Five movies avout how you can use Gimps different tools for restoration of old photos.
GIMP Video Tutorials – Videos that show the different tools and how to use them
GIMP tutorials more video on You tube.
Meet the GIMP – podcasts about Gimp.

Tutorials

New! Gimptalk forum -a beginners startpoint
Tutorials at Gimpusers – tutorials in categories at Gimpusers
Tone Mapping i Gimp
Gimptricks – Gimps.de tutorials on german, english – a german site about Gimp in two languages.
Gimpology – another website with tutorials for Gimp,
Tutorials about Gimp
Gimp tutorials – even more tutorials about gimp
Gimp at Open source photo, tutorials

• Add a vignette
  
• Install Focus Blur plugin
• Leveling the horisont
• Haze removal
• Tone enhancement
• Split toning
• GIMP Scripts
• Simulate Filmgrain
• Crop to a ratio

GIMP Tutorials – There is alot of good tutorials at Gimps website. They have sorted them into level of difficulty. You also find information about how to start with scripting.
Linuxchics course about Gimp

Scripts och plugins

New! Gimpstuff -brushes, patterns and other stuff
Separate+ – plugin to seperate your RGB coulours to CMYK
GMic – GMic is a new collection of plugins and scripts that will save the day. It is GreycStoration in a new better GUI with lots of more features and it is developed fast. I have a short article about GMic.
Highpass filter – a relative new highpass filter with 5 different variants.
Script Photoeffects – a page that shows how they change a picture. A nice collection.
Gimpactions – a collection of plugins at Deviantart
Photocomix collection of resources – Photocomix collects plugins, scripts etc
Plugins till Gimp – here you will find most plugins and scripts avaiable to Gimp. Some is very useful Smart Sharpen will sharpen the edges but not blurred parts of the picture.
Gimp FX-foundry,Sourceforge – a collection with some very useful scripts suited for Gimp 2.4.

Brushes, patterns and hacks

Curves for you to upload that simulates old photofilm
Instruction how to create brushes in Gimp and a couple of grunge brushes to download.
Hawksmont Brushes – here you will find brushes both for Gimp and for Photoshop.
130 Web 2.0 Gradients – 130 gradient that will help you make web 2.0 graphics.
Brushes to Gimp at Devianart
Patterns and colours – here you find alot of patterns and some abut colours.
GIMPshop - a hack that makes Gimp look like photoshop. I myself prefer the gimp Gui, but i think it is a matter of habits.
GimPhoto – even one more hack that makes Gimp into photoshop lookalike. This is build upon Gimp 2.4 at least.

Forum and Groups

New! Group of Gimp in Ipernity – Not many members now but why not join in…
Gimptalk – You will find alot of tutorials and pugins etc. and their forum are probably the largest.
Gimp Beginners – a group on Flickr for you that is new to Gimp and want to learn more.
Flickr Gimpusers – over 500 Flickrusers that are deep into Gimp. Alot of experience and the discussions are of high level. Beginners find alot help here.
GimpTacular på Deviantart – a group for those who loves Gimp.
Gimpusers – community med massor av nyheter, tutorials och mycket mer.
Wiki hos Gimp.org – mostly for developers but there is some informations for the common user.
Gimper – Gimp forum and here you will find the Gimp users for Mac.

Blogs about Gimp

New! Iffles – Takes up some about gimp and are a good startingpoint

SGlider12
GIMPers Anonymous

Other sites about pictures

Jiscmedia – a good startsite about digital photo and pictures.
Collection of Gimpresources – a page like this with alot of links to resources about Gimp.