WorkTo work in the Netherlands, residents of the EU/EEA member states do not require resident permits (read more in Immigration). After you have been here for three months, you should register with the IND (Immigration and Naturalisation Service). When you register, you must provide documents to verify the purpose of your stay. After registration, you will immediately receive proof of registration in the form of a sticker, which will be attached to your passport (or other proof of identity).
For more information, see the IND website at IND www.ind.nl. You will find a "residence wizard" on that website, where you will find the rules for staying in the Netherlands for you and your family.
If you are a Bulgarian or Romanian national, you are not obligated to apply to a municipality for a residence permit or an EU document (although this is advisable). Because you will still face restrictions to the labour market, the registration procedure at IND counters that applies to other citizens of the EU does not apply to you.
Since 1 January 2005, everyone aged 14 or older must be able to show proof of identity. If you are an EU or EEA national, you can use your passport or EU/EEA identity card as proof of identification.