I regularly fish the Nene in north Northants around the border with Cambs/Peterborough. Great for general chubbing and some cracking carp around Fotheringhay and more in the direction of Peterborough, around Yarwell is great chubbing again (my pb chub was just over 6lb from here) and even some nice Barbel at Wansford lock, especially in the weir pool.
I find these areas respond particularly well to luncheon meat(I coat mine in curry powder which the barbel seem to much prefer to plain) fishing on the quiver, trotted bread for chub or spicy/meaty paste for general. Or a day on maggots will produce loads of roach, small chub and dace.
Wellingborough Nene AC have a few stretches of both Nene and Ouse, check out their website http://www.wdnac.org.uk/ year is 30 (Jan/Dec), you may be able to get a reduced price now as the year is half gone.
Then just outside Irthlingborough we have Glebe Meadow fishery (4 per day). Parking behind most pegs. Call Kevin Goodman on 01933 651305 as you need the code for the padlock to get in. Kevin will put you on the right peg for whatever you want to fish for.
Irthlingborough club has most of the stretches around the town. You can get a ticket from Andy Webster at the tackle shop in town (and maybe meet Genus 9 if you are unlucky), sorry don't know the current cost.
Neither Wellingborough nor Irthlingborough do day tickets.