Design a logo with words and graphics

I would like a logo to go on the banner of a private speech and language therapy website. The same logo will also be used on letterheads, business cards, etc.
I would like the words

Great to Talk

Which in .co.uk form is our website name to be at the top of the logo and

Speech and Language Therapy

to go at the bottom.

I would like the logo to be in cartoon form, showing children, preferably different ages (toddler to teenager), very simple and using primary colours red, blue green with a black outline and parts of the characters in black.

The images must be suitable for integration with the look and feel with other graphics, as well as be used on a web site banner. The images must be easy to shrink/expand hence in a vector format using vector (true type) fonts such as: SVG or gimp XCF, Adobe Illustrator AI/art/ps/eps, WMF, Photoshop.

Ideally the font and/or font style should match with an appropriate easily accessible (standard) web site font for use in HTML headers etc. but this does not need to be an exact match though the look and feel must integrate nicely. When submitting a design it may be necessary to experiment with a range of different fonts and size ratios between the characters and the lettering.

The logo will be ours to use in any way we need in the future.