Let me start with what you should not do. Calling the the listing agent of a property to show you the home. That can indeed place you on the road to dual agency and cause complications down the road if you want to bring in a buyer's agent at a later date.
Dual agency is a terrible deal for you and I would avoid it at all costs. One agent cannot represent both sides in a transaction. It's simply not possible. It also creates a situation where an unnaturally large commission is created, which can cause the agent to develop tremendous loyalty to the deal, and not to you OR the seller.
So to avoid that, simply retain your own buyers agent. Many of my relationships with clients in a buyer's agent capacity are measured in months to years. If you were honest and upfront as someone else mentions, most agents would be happy to work with you. You can offload some of the wasted time by driving past the exteriors of homes you're interested in and only scheduling interior inspections of homes that are of particularly high interest.
If you have any other questions, just contact me through my website and I'll be happy to answer them. Good luck Lisa!
973-228-1000 ext 132
Get some recommendations from family or friends for an agent they used and liked. If you can't get any recommendations, look through websites (like Trulia!) and agent websites. Then, talk to those agents one by one and you should make some kind of connection with one of them. Explain your situation to each agent and weigh the responses to see who understands you best and will work under your terms.
You also can go to the open houses for the listings you like and others. Open houses are a great place to find an agent to work with. Just be sure to tell them that you are working with someone or you will be bombarded with different agents calling and emailing you (if you give them your information.) Then, you can pick and choose your agent on your terms.
The way you are going about looking is very common these days as most buyers start their search on the internet. And, while most properties are on the internet, some are not. Find a buyers agent who works with FSBO's, too and you will get even more properties to consider.
The reason you don't want to see the homes with the seller's brokerage company is that in NJ we have what is known as procuring cause. If you see a house with the sellers' company then try to bring in your own agent, the sellers' broker legally has procurring cause as they have showed you the house first.
Find an agent you like. It may turn out to be someone who will work with you as a dual agent. However, if you trust and respect that person first and foremost, you should know they will do a good job for you in either buyers agent or buyers agent/dual disclosed.
Going to a property without a buyer's agent doesn't necessarily obligate you to use the listing agent as a dual agent (although new construction can be an entirely different animal) but it can sure complicate the issue big time.
Give a buyer's agent a call... we're not that intimidating, and we're not that scary... in fact I think you might find one charming and helpful.