It's crucial to get this sorted as early on as possible, as it shocked me to find out that only two-fifths of single parents receive maintenance from their ex-partner.
From personal experience the CSA (Child Support Agency) were less than useless when I became a single parent in 2003, and I spent the first 3 years without any payments at all from my ex-husband. There's plenty of advice on this Child Maintenance website as well as the Gingerbread and One Space sites.
Many single parents work part-time (myself included) and there are laws that protect the employment rights of the part-time worker. I've experienced some discrimination as a part-time worker, mainly due to ignorance of my employer at the time so equip yourself with the right information. This TUC website gives information on how equal rights for part-time workers includes pay, holidays, redundancy, pensions and training. Don't forget, the law is on your side.
The recent budget changes to Working Tax Credit are listed here and although many of the changes will make a difference to couples with children you should still check and make sure you're getting your full entitlement.
Make sure you are getting everything you are entitled to and that includes free school meals for your child/ren. There are lots of parents who don't realise they are entitled - don't be embarrassed about applying for them, they can make a considerable difference to your weekly budget.
For general information on a whole host of subjects affecting single parents, these website offer all you should need.
One Space has a really good website, full of information and support for single parents. They also have a solicitor available to give legal advice, as well as links to local services in your area.
There is also a number of e-learning courses for single parents including the Freedom programme for people who have experienced domestic abuse, life coaching, ways into work and how to build your CV.
Gingerbread is a great place to find support on a whole range of subjects. Their website offers information on money, housing, relationships and benefits and they also have a variety of fact sheets that can be downloaded. Recently they launched an email advice package for single parents including a new one about child maintenance. Gingerbread also offer a helpline, information on local support groups and a discussion forum.
The DirectGov website also offers specific information on financial help for lone parents, including income support, child maintenance and childcare costs.