I have one of these - it's a decent camera but I hardly use it since I upgraded to the E-PL3 (current model although E-PL5 successor is out soon).
The original 14-42 lens is not great (the mark i that comes with the E-PL1) and the camera is butt ugly too.

You really need a good prime like the 20mm Panasonic or the 45mm Olympus to take full advantage of these micro four thirds cameras.
The camera is quite basic in some ways - feels a bit cheap and has a very small low-res lcd screen and slightly awkward buttons on the back. But the E-PL1 takes great pictures and the Oly jpeg engine is great if you don't want to pp.
However I would suggest the E-PM1 which will give you faster AF, a better 14-42 lens (mkii) and a smaller, more attractive body.

It's pretty cheap now that the E-PM2 has been announced: £227/£230 with 14-42:
http://www.amazon.co.uk/exec/obidos/ASIN/B0058GI828/1567/ref=nosim (silver)
http://www.wilkinson.co.uk/olympus-e-pm1-mini-af-14-42-ii-r-black.html (black)
There is a good user review of the E-PM1 here:
http://www.mu-43.com/f102/my-epm1-review-18929/
Plus an E-PL1 vs E-PM1 discussion here:
http://www.mu-43.com/f42/best-value-1st-m4-3-e-pl1-vs-e-pm1-24296/
If you prefer the tilting screen and mode dial of the E-PL3, you can pick that up for £200.99 body only:
http://www.srsmicrosystems.co.uk/6488/Olympus-PEN-E-PL3-Black-Digital-Camera-Body.html It's basically identical to the E-PM1 apart from the tilt screen, mode dial and an extra control button on the rear.
If you want to add prime lenses is starts getting expensive though - 20mm Panasonic pancake is a great walk around lens and keeps the camera + lens combo small, but it's around £270 for that lens. The 14mm lens is even smaller and is cheaper (new on ebay around £120 split from a kit) but a bit wide for general use. Bear in mind the crop factor on micro four thirds camera is x2.
Anyway (in summary) - unless the E-PL1 you have been offered is a stonking bargain I would go for the more recent E-PM1.