Looking at the pictures I took with the N95 recently and then the difference some tweaks made the results significantly more vivid and rich in colour, I decided (on some requests) to do a quick tutorial on how to achieve the results.
In very simple 4 steps you can make your Mobile snaps from looking slightly colourless and under-saturated to something much more vivid and colourful.

You will need to have some experience in using any sort of graphics editor or photo manipulating software. I use Adobe Photoshop, you can use GIMP, Paint Shop Pro etc... to do the same things, but they may not have similar menu structures. Photoshop and GIMP do, and as GIMP is freeware I would recommend it for those that may need some software.

Step One
Getting the balance right. Using some of the auto presets you can allow the software to adjust the levels and contrast using:

Image > Adjustments > Auto Levels
Image > Adjustments > Auto Contrast

The results should be slightly darker and more defined around the edges, this may not be easily noticeable, but I assure you the picture has changed. See below:

Step Two:
Now we will adjust the intensity of the colour. This can be tricky with pictures with varying colour tones, but as my picture was predominantly green based it was a simple process of adjusting the intensity of the greens. You can adjust all the values - shadow, midtones and highlights to your desire by going to:

Image > Adjustments > Colour Balance

You will have to use your own judgement on this as there is no one simple solution as all pictures are different. Use your own judgement to adjust them as desired. I decided to not have it too intense at this point as the next step will make it more vivid. Results below:

Step Three:
In this penultimate step you will use an appropriate filter to get the final look of the picture. Firstly create a new duplicate layer of the current image (the quickest way is to use Ctrl + J), but you can also go to:

Layer > Duplicate Layer make sure to add it into your current project.

Now making sure you have the copy layer selected you need to go into layer style (simply double click on the layer) or go to:

Layer > Layer Style > Blending Options

This should bring up the following screen:

Using the Blending Mode drop down menu you can use the various filters for adjusting the final look of the picture. I'd recommend using some of the more subtle layer effects, for this particular picture I've used Soft Light, which enhances the picture slightly, not making it too vivid and overwhelming. See Below:

Step Four:
This is a final step just to enhance the image focus by adding a border and glowing edge. You can skip this if you like, but I find adding a border enhances the picture slightly and gives it an edge (literally).
The process is simple, just add a new blank layer on top:

Layer > New Layer > Layer... Name it Border for organisation sake.

You can decide how big you want the border to be. To get a perfectly balanced border I usually mark one side and move the selection across to fill the area, repeating this for all 4 sides. I've found this to be most easiest and painless way.

After this is done, you need to go back into the Layer Style Menu (simply double click on the layer) or go to:

Layer > Layer Style > Blending Options

Once there, we will adjust the opacity of the border as desired, I usually opt for 75-80%. Then select the Stroke option on the left and use the following settings to achieve a nice glow near the border edges:
Size: 1
Position: Outside
Blend Mode: Overlay
Opacity: 100
Fill Type: Colour
Colour: White (ffffff)

You should have your final results now!

You can always play with the settings and adjust them to your liking, sometimes it's necessary! This guide is not written in stone, it's aimed to use as a guide to get you tweaking your own pictures.