Speedlights for nikon?

Hi
i was wondering if you could help me a little
i have a camera: nikon d 60 and i would like to buy a speedlight and i don't know which one to choose
sb 700 or sb 900. Do they both fit to the nikon d60? Which one is better?

The Nikon D60 does not have the advantage of Nikon wireless flash control (CLS), so if you wanted to use them off camera, then you'd need to fire them in manual using radio triggers.

On camera, they'll auto flash meter (TTL) with the Nikon. The SB900 is technically better, but it has a lot of 'bells & whistles' that you'll probably never need. The SB700 would almost certainly be better for your needs.

It is always better if you can to use your flash OFF camera - you have control over directionality and can modify the flash with umbrellas or softboxes to make it softer.
Seeing as you'd have to use a Nikon speedlight in manual off camera anyway, why waste money (these units are expensive) on a Nikon SB when you could get a cheaper manual flash.

I have Nikon speedlights, but I also have Yongnuo flashes (460-II and a 560) which cost £40 and £60 respectively. I fire those off camera, setting the output manually with a set of radio triggers (RF602's - £27).

You could probably put together a 2 light setup, with an umbrella/softbox for the price of a single SB900.

Both will work perfectly. The SB-900 is more powerful and better in general, but for your intents and purposes it won't make any practical difference that justifies the additional cost over the SB-700.

You may also give Yongnuo flashes a thought. The YN468 costs just $125 or so, has TTL on the camera just like a Nikon speedlight (not entirely as "smart" but good enough), and can be triggered off camera as an optical slave with your popup flash without any additional hardware - that's the real fun.
Those two Nikon flashes can't be triggered off camera without additional hardware, at least not with your camera (The D90 and higher up can, using Nikon CLS)

If you're serious about photography and flash use, then you'll be better off with two or three off camera Yongnuo flashes than the single Nikon speedlight that you can get for the same money. On the long run, for improved reliability in triggering them off camera as opposed to the optical slave mode, you may also consider radio triggers, but these aren't required right from the start.

The YN 468 is a bit weak in terms of its maximum output, the YN 465 has more power but no optical slave mode, the YN 560 has the most power but no TTL on the camera.

Any will do. If you can afford it, get the more powerful one, the SB900. More light is always better, you can tone it down if too much.

A 900 will dwarf your camera. A 700 will fit your camera much better.

You could also consider a third party flashgun that is fully compatible with the Nikon Creative Lighting System. The Nissin Di866 (about £199) is actually more powerful that the SB900, fully compatible and with a colour LCD display. I use one of these together with the SB900s and SB800s (now discontinued).

See this video on You Tube:

You can consider Nikon SB-900 AF Speedlight Flash for Nikon Digital SLR Cameras

High-quality flash for standalone use or as part of a comprehensive lighting system
Commander mode controls up to 3 Speedlight groups or unlimited individual Speedlights
4 wireless channel options; prominent master and remote control switch for wireless operation
Auto power zoom coverage ranges from 17 to 200mm (FX format) to 12 to 200mm (DX format)
3 light distribution patterns; measures 3 x 5.7 x 4.7 inches (W x H x D) and weighs 14.6 ounces